diff --git a/anagrams.tlv b/anagrams.tlv
index 4678bfa..14f3d21 100644
--- a/anagrams.tlv
+++ b/anagrams.tlv
@@ -61,21 +61,6 @@
     >end
     >
     >-- TODO: backport utf-8 support from Lua 5.3
-- __teliva_timestamp: original
-  debugy:
-    >debugy = 5
-- __teliva_timestamp: original
-  dbg:
-    >-- helper for debug by print; overlay debug information towards the right
-    >-- reset debugy every time you refresh screen
-    >function dbg(window, s)
-    >  local oldy = 0
-    >  local oldx = 0
-    >  oldy, oldx = window:getyx()
-    >  window:mvaddstr(debugy, 60, s)
-    >  debugy = debugy+1
-    >  window:mvaddstr(oldy, oldx, '')
-    >end
 - __teliva_timestamp: original
   check_eq:
     >function check_eq(x, expected, msg)
@@ -177,8 +162,7 @@
     >  end
     >  return result
     >end
-- __teliva_timestamp:
-    >Mon Feb 21 17:45:04 2022
+- __teliva_timestamp: original
   sort_letters:
     >function sort_letters(s)
     >  tmp = {}
@@ -220,12 +204,6 @@
     >    l[#l+1] = elems[i]
     >  end
     >end
-- __teliva_timestamp: original
-  Window:
-    >Window = curses.stdscr()
-- __teliva_timestamp: original
-  doc:blurb:
-    >Show all anagrams of a given word
 - __teliva_timestamp: original
   menu:
     >-- To show app-specific hotkeys in the menu bar, add hotkey/command
@@ -233,6 +211,12 @@
     >menu = {
     >  {'^h', 'backspace'},
     >}
+- __teliva_timestamp: original
+  Window:
+    >Window = curses.stdscr()
+- __teliva_timestamp: original
+  doc:blurb:
+    >Show all anagrams of a given word
 - __teliva_timestamp: original
   word:
     >word = ''
diff --git a/commander.tlv b/commander.tlv
index 5416f64..6b80304 100644
--- a/commander.tlv
+++ b/commander.tlv
@@ -62,90 +62,10 @@
     >
     >-- TODO: backport utf-8 support from Lua 5.3
 - __teliva_timestamp: original
-  debugy:
-    >debugy = 5
-- __teliva_timestamp: original
-  dbg:
-    >-- helper for debug by print; overlay debug information towards the right
-    >-- reset debugy every time you refresh screen
-    >function dbg(window, s)
-    >  local oldy = 0
-    >  local oldx = 0
-    >  oldy, oldx = window:getyx()
-    >  window:mvaddstr(debugy, 60, s)
-    >  debugy = debugy+1
-    >  window:mvaddstr(oldy, oldx, '')
-    >end
-- __teliva_timestamp: original
-  check_eq:
-    >function check_eq(x, expected, msg)
-    >  if x == expected then
-    >    Window:addch('.')
-    >  else
-    >    print('F - '..msg)
-    >    print('  expected '..tostring(expected)..' but got '..x)
-    >    teliva_num_test_failures = teliva_num_test_failures + 1
-    >    -- overlay first test failure on editors
-    >    if teliva_first_failure == nil then
-    >      teliva_first_failure = msg
-    >    end
-    >  end
-    >end
-- __teliva_timestamp: original
-  map:
-    >-- only for arrays
-    >function map(l, f)
-    >  result = {}
-    >  for _, x in ipairs(l) do
-    >    table.insert(result, f(x))
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp: original
-  reduce:
-    >-- only for arrays
-    >function reduce(l, f, init)
-    >  result = init
-    >  for _, x in ipairs(l) do
-    >    result = f(result, x)
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp: original
-  filter:
-    >-- only for arrays
-    >function filter(l, f)
-    >  result = {}
-    >  for _, x in ipairs(l) do
-    >    if f(x) then
-    >      table.insert(result, x)
-    >    end
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp: original
-  find_index:
-    >function find_index(arr, x)
-    >  for n, y in ipairs(arr) do
-    >    if x == y then
-    >      return n
-    >    end
-    >  end
-    >end
-- __teliva_timestamp: original
-  trim:
-    >function trim(s)
-    >  return s:gsub('^%s*', ''):gsub('%s*$', '')
-    >end
-- __teliva_timestamp: original
-  split:
-    >function split(s, d)
-    >  result = {}
-    >  for match in (s..d):gmatch("(.-)"..d) do
-    >    table.insert(result, match);
-    >  end
-    >  return result
-    >end
+  menu:
+    >-- To show app-specific hotkeys in the menu bar, add hotkey/command
+    >-- arrays of strings to the menu array.
+    >menu = {}
 - __teliva_timestamp: original
   Window:
     >Window = curses.stdscr()
@@ -161,11 +81,6 @@
     >  end
     >  window:refresh()
     >end
-- __teliva_timestamp: original
-  menu:
-    >-- To show app-specific hotkeys in the menu bar, add hotkey/command
-    >-- arrays of strings to the menu array.
-    >menu = {}
 - __teliva_timestamp: original
   update:
     >function update(window)
@@ -197,3 +112,6 @@
     >    update(Window)
     >  end
     >end
+- __teliva_timestamp: original
+  doc:blurb:
+    >beginnings of a file browser..
diff --git a/gemini.tlv b/gemini.tlv
index ed0cad7..3a163f0 100644
--- a/gemini.tlv
+++ b/gemini.tlv
@@ -76,21 +76,6 @@
     >  debugy = debugy+1
     >  window:mvaddstr(oldy, oldx, '')
     >end
-- __teliva_timestamp: original
-  check_eq:
-    >function check_eq(x, expected, msg)
-    >  if x == expected then
-    >    Window:addch('.')
-    >  else
-    >    print('F - '..msg)
-    >    print('  expected '..tostring(expected)..' but got '..x)
-    >    teliva_num_test_failures = teliva_num_test_failures + 1
-    >    -- overlay first test failure on editors
-    >    if teliva_first_failure == nil then
-    >      teliva_first_failure = msg
-    >    end
-    >  end
-    >end
 - __teliva_timestamp: original
   map:
     >-- only for arrays
@@ -355,7 +340,7 @@
   init_colors:
     >function init_colors()
     >  for i=0,7 do
-    >    curses.init_pair(i, i, 8)
+    >    curses.init_pair(i, i, -1)
     >  end
     >  curses.init_pair(8, 7, 0)
     >  curses.init_pair(9, 7, 1)
@@ -364,7 +349,7 @@
     >  curses.init_pair(12, 7, 4)
     >  curses.init_pair(13, 7, 5)
     >  curses.init_pair(14, 7, 6)
-    >  curses.init_pair(15, 8, 15)
+    >  curses.init_pair(15, -1, 15)
     >end
 - __teliva_timestamp: original
   main:
diff --git a/life.tlv b/life.tlv
index 0693e7f..78cfa9f 100644
--- a/life.tlv
+++ b/life.tlv
@@ -16,6 +16,370 @@
 #
 # If these constraints are violated, Teliva may unceremoniously crash. Please
 # report bugs at http://akkartik.name/contact
+- __teliva_timestamp: original
+  str_helpers:
+    >-- some string helpers from http://lua-users.org/wiki/StringIndexing
+    >
+    >-- index characters using []
+    >getmetatable('').__index = function(str,i)
+    >  if type(i) == 'number' then
+    >    return string.sub(str,i,i)
+    >  else
+    >    return string[i]
+    >  end
+    >end
+    >
+    >-- ranges using (), selected bytes using {}
+    >getmetatable('').__call = function(str,i,j)
+    >  if type(i)~='table' then
+    >    return string.sub(str,i,j)
+    >  else
+    >    local t={}
+    >    for k,v in ipairs(i) do
+    >      t[k]=string.sub(str,v,v)
+    >    end
+    >    return table.concat(t)
+    >  end
+    >end
+    >
+    >-- iterate over an ordered sequence
+    >function q(x)
+    >  if type(x) == 'string' then
+    >    return x:gmatch('.')
+    >  else
+    >    return ipairs(x)
+    >  end
+    >end
+    >
+    >-- insert within string
+    >function string.insert(str1, str2, pos)
+    >  return str1:sub(1,pos)..str2..str1:sub(pos+1)
+    >end
+    >
+    >function string.remove(s, pos)
+    >  return s:sub(1,pos-1)..s:sub(pos+1)
+    >end
+    >
+    >-- TODO: backport utf-8 support from Lua 5.3
+- __teliva_timestamp: original
+  debugy:
+    >debugy = 5
+- __teliva_timestamp: original
+  dbg:
+    >-- helper for debug by print; overlay debug information towards the right
+    >-- reset debugy every time you refresh screen
+    >function dbg(window, s)
+    >  local oldy = 0
+    >  local oldx = 0
+    >  oldy, oldx = window:getyx()
+    >  window:mvaddstr(debugy, 60, s)
+    >  debugy = debugy+1
+    >  window:mvaddstr(oldy, oldx, '')
+    >end
+- __teliva_timestamp: original
+  check_eq:
+    >function check_eq(x, expected, msg)
+    >  if eq(x, expected) then
+    >    Window:addch('.')
+    >  else
+    >    print('F - '..msg)
+    >    print('  expected '..str(expected)..' but got '..str(x))
+    >    teliva_num_test_failures = teliva_num_test_failures + 1
+    >    -- overlay first test failure on editors
+    >    if teliva_first_failure == nil then
+    >      teliva_first_failure = msg
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  eq:
+    >function eq(a, b)
+    >  if type(a) ~= type(b) then return false end
+    >  if type(a) == 'table' then
+    >    if #a ~= #b then return false end
+    >    for k, v in pairs(a) do
+    >      if b[k] ~= v then
+    >        return false
+    >      end
+    >      return true
+    >    end
+    >  end
+    >  return a == b
+    >end
+- __teliva_timestamp: original
+  str:
+    >-- smarter tostring
+    >-- slow; used only for debugging
+    >function str(x)
+    >  if type(x) == 'table' then
+    >    local result = ''
+    >    result = result..#x..'{'
+    >    for k, v in pairs(x) do
+    >      result = result..str(k)..'='..str(v)..', '
+    >    end
+    >    result = result..'}'
+    >    return result
+    >  end
+    >  return tostring(x)
+    >end
+- __teliva_timestamp: original
+  map:
+    >-- only for arrays
+    >function map(l, f)
+    >  result = {}
+    >  for _, x in ipairs(l) do
+    >    table.insert(result, f(x))
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  reduce:
+    >-- only for arrays
+    >function reduce(l, f, init)
+    >  result = init
+    >  for _, x in ipairs(l) do
+    >    result = f(result, x)
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  filter:
+    >-- only for arrays
+    >function filter(l, f)
+    >  result = {}
+    >  for _, x in ipairs(l) do
+    >    if f(x) then
+    >      table.insert(result, x)
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  find_index:
+    >function find_index(arr, x)
+    >  for n, y in ipairs(arr) do
+    >    if x == y then
+    >      return n
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  trim:
+    >function trim(s)
+    >  return s:gsub('^%s*', ''):gsub('%s*$', '')
+    >end
+- __teliva_timestamp: original
+  split:
+    >function split(s, d)
+    >  result = {}
+    >  for match in (s..d):gmatch("(.-)"..d) do
+    >    table.insert(result, match);
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp:
+    >Mon Feb 21 17:45:04 2022
+  sort_letters:
+    >function sort_letters(s)
+    >  tmp = {}
+    >  for i=1,#s do
+    >    table.insert(tmp, s[i])
+    >  end
+    >  table.sort(tmp)
+    >  local result = ''
+    >  for _, c in pairs(tmp) do
+    >    result = result..c
+    >  end
+    >  return result
+    >end
+    >
+    >function test_sort_letters(s)
+    >  check_eq(sort_letters(''), '', 'test_sort_letters: empty')
+    >  check_eq(sort_letters('ba'), 'ab', 'test_sort_letters: non-empty')
+    >  check_eq(sort_letters('abba'), 'aabb', 'test_sort_letters: duplicates')
+    >end
+- __teliva_timestamp: original
+  count_letters:
+    >function count_letters(s)
+    >  local result = {}
+    >  for i=1,string.len(s) do
+    >    local c = s[i]
+    >    if result[c] == nil then
+    >      result[c] = 1
+    >    else
+    >      result[c] = result[c] + 1
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  append:
+    >-- concatenate list 'elems' into 'l', modifying 'l' in the process
+    >function append(l, elems)
+    >  for i=1,#elems do
+    >    l[#l+1] = elems[i]
+    >  end
+    >end
+- __teliva_timestamp: original
+  menu:
+    >-- To show app-specific hotkeys in the menu bar, add hotkey/command
+    >-- arrays of strings to the menu array.
+    >menu = {}
+- __teliva_timestamp: original
+  window:
+    >-- constructor for fake screen and window
+    >-- call it like this:
+    >--   local w = window{
+    >--     kbd=kbd('abc'),
+    >--     scr=scr{h=5, w=4},
+    >--   }
+    >-- eventually it'll do everything a real ncurses window can
+    >function window(h)
+    >  h.__index = h
+    >  setmetatable(h, h)
+    >  h.__index = function(table, key)
+    >    return rawget(h, key)
+    >  end
+    >  h.getch = function(self)
+    >    return table.remove(h.kbd, 1)
+    >  end
+    >  h.addch = function(self, c)
+    >    local scr = self.scr
+    >    if scr.cursy <= scr.h then
+    >      scr[scr.cursy][scr.cursx] = c
+    >      scr.cursx = scr.cursx+1
+    >      if scr.cursx > scr.w then
+    >        scr.cursy = scr.cursy+1
+    >        scr.cursx = 1
+    >      end
+    >    end
+    >  end
+    >  h.addstr = function(self, s)
+    >    for i=1,string.len(s) do
+    >      self:addch(s[i])
+    >    end
+    >  end
+    >  h.mvaddch = function(self, y, x, c)
+    >    self.scr.cursy = y
+    >    self.scr.cursx = x
+    >    self.addch(c)
+    >  end
+    >  h.mvaddstr = function(self, y, x, s)
+    >    self.scr.cursy = y
+    >    self.scr.cursx = x
+    >    self:addstr(s)
+    >  end
+    >  return h
+    >end
+- __teliva_timestamp: original
+  kbd:
+    >function kbd(keys)
+    >  local result = {}
+    >  for i=1,string.len(keys) do
+    >    table.insert(result, keys[i])
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  scr:
+    >function scr(props)
+    >  props.cursx = 1
+    >  props.cursy = 1
+    >  for y=1,props.h do
+    >    props[y] = {}
+    >    for x=1,props.w do
+    >      props[y][x] = ' '
+    >    end
+    >  end
+    >  return props
+    >end
+- __teliva_timestamp:
+    >Thu Mar  3 22:04:15 2022
+  check_screen:
+    >function check_screen(window, contents, message)
+    >  local x, y = 1, 1
+    >  for i=1,string.len(contents) do
+    >    check_eq(contents[i], window.scr[y][x], message..'/'..y..','..x)
+    >    x = x+1
+    >    if x > window.scr.w then
+    >      y = y+1
+    >      x = 1
+    >    end
+    >  end
+    >end
+    >
+    >-- putting it all together, an example test of both keyboard and screen
+    >function test_check_screen()
+    >  local lines = {
+    >    c='123',
+    >    d='234',
+    >    a='345',
+    >    b='456',
+    >  }
+    >  local w = window{
+    >    kbd=kbd('abc'),
+    >    scr=scr{h=3, w=5},
+    >  }
+    >  local y = 1
+    >  while true do
+    >    local c = w:getch()
+    >    if c == nil then break end
+    >    w:mvaddstr(y, 1, lines[c])
+    >    y = y+1
+    >  end
+    >  check_screen(w, '345  '..
+    >                  '456  '..
+    >                  '123  ',
+    >              'test_check_screen')
+    >end
+- __teliva_timestamp: original
+  start_reading:
+    >-- primitive for reading files from a file system (or, later, network)
+    >-- returns a channel or nil on error
+    >-- read lines from the channel using :recv()
+    >-- recv() on the channel will indicate end of file.
+    >function start_reading(fs, filename)
+    >  local result = task.Channel:new()
+    >  local infile = io.open(filename)
+    >  if infile == nil then return nil end
+    >  task.spawn(reading_task, infile, result)
+    >  return result
+    >end
+    >
+    >function reading_task(infile, chanout)
+    >  for line in infile:lines() do
+    >    chanout:send(line)
+    >  end
+    >  chanout:send(nil)  -- eof
+    >end
+- __teliva_timestamp: original
+  start_writing:
+    >-- primitive for writing files to a file system (or, later, network)
+    >-- returns a channel or nil on error
+    >-- write to the channel using :send()
+    >-- indicate you're done writing by calling :close()
+    >-- file will not be externally visible until :close()
+    >function start_writing(fs, filename)
+    >  local result = task.Channel:new()
+    >  local initial_filename = os.tmpname()
+    >  local outfile = io.open(initial_filename, 'w')
+    >  if outfile == nil then return nil end
+    >  result.close = function()
+    >    result:send(nil)  -- end of file
+    >    outfile:close()
+    >    os.rename(initial_filename, filename)
+    >  end
+    >  task.spawn(writing_task, outfile, result)
+    >  return result
+    >end
+    >
+    >function writing_task(outfile, chanin)
+    >  while true do
+    >    local line = chanin:recv()
+    >    if line == nil then break end  -- end of file
+    >    outfile:write(line)
+    >  end
+    >end
 - __teliva_timestamp: original
   grid:
     >-- main data structure
diff --git a/sieve.tlv b/sieve.tlv
index 92c086a..9677af4 100644
--- a/sieve.tlv
+++ b/sieve.tlv
@@ -16,249 +16,14 @@
 #
 # If these constraints are violated, Teliva may unceremoniously crash. Please
 # report bugs at http://akkartik.name/contact
-- __teliva_timestamp: original
-  str_helpers:
-    >-- some string helpers from http://lua-users.org/wiki/StringIndexing
-    >
-    >-- index characters using []
-    >getmetatable('').__index = function(str,i)
-    >  if type(i) == 'number' then
-    >    return string.sub(str,i,i)
-    >  else
-    >    return string[i]
-    >  end
-    >end
-    >
-    >-- ranges using (), selected bytes using {}
-    >getmetatable('').__call = function(str,i,j)
-    >  if type(i)~='table' then
-    >    return string.sub(str,i,j)
-    >  else
-    >    local t={}
-    >    for k,v in ipairs(i) do
-    >      t[k]=string.sub(str,v,v)
-    >    end
-    >    return table.concat(t)
-    >  end
-    >end
-    >
-    >-- iterate over an ordered sequence
-    >function q(x)
-    >  if type(x) == 'string' then
-    >    return x:gmatch('.')
-    >  else
-    >    return ipairs(x)
-    >  end
-    >end
-    >
-    >-- insert within string
-    >function string.insert(str1, str2, pos)
-    >  return str1:sub(1,pos)..str2..str1:sub(pos+1)
-    >end
-    >
-    >function string.remove(s, pos)
-    >  return s:sub(1,pos-1)..s:sub(pos+1)
-    >end
-    >
-    >-- TODO: backport utf-8 support from Lua 5.3
-- __teliva_timestamp: original
-  debugy:
-    >debugy = 5
-- __teliva_timestamp: original
-  dbg:
-    >-- helper for debug by print; overlay debug information towards the right
-    >-- reset debugy every time you refresh screen
-    >function dbg(window, s)
-    >  local oldy = 0
-    >  local oldx = 0
-    >  oldy, oldx = window:getyx()
-    >  window:mvaddstr(debugy, 60, s)
-    >  debugy = debugy+1
-    >  window:mvaddstr(oldy, oldx, '')
-    >end
-- __teliva_timestamp: original
-  check_eq:
-    >function check_eq(x, expected, msg)
-    >  if eq(x, expected) then
-    >    Window:addch('.')
-    >  else
-    >    print('F - '..msg)
-    >    print('  expected '..str(expected)..' but got '..str(x))
-    >    teliva_num_test_failures = teliva_num_test_failures + 1
-    >    -- overlay first test failure on editors
-    >    if teliva_first_failure == nil then
-    >      teliva_first_failure = msg
-    >    end
-    >  end
-    >end
-- __teliva_timestamp: original
-  eq:
-    >function eq(a, b)
-    >  if type(a) ~= type(b) then return false end
-    >  if type(a) == 'table' then
-    >    if #a ~= #b then return false end
-    >    for k, v in pairs(a) do
-    >      if b[k] ~= v then
-    >        return false
-    >      end
-    >      return true
-    >    end
-    >  end
-    >  return a == b
-    >end
-- __teliva_timestamp: original
-  str:
-    >-- smarter tostring
-    >-- slow; used only for debugging
-    >function str(x)
-    >  if type(x) == 'table' then
-    >    local result = ''
-    >    result = result..#x..'{'
-    >    for k, v in pairs(x) do
-    >      result = result..str(k)..'='..str(v)..', '
-    >    end
-    >    result = result..'}'
-    >    return result
-    >  end
-    >  return tostring(x)
-    >end
-- __teliva_timestamp: original
-  map:
-    >-- only for arrays
-    >function map(l, f)
-    >  result = {}
-    >  for _, x in ipairs(l) do
-    >    table.insert(result, f(x))
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp: original
-  reduce:
-    >-- only for arrays
-    >function reduce(l, f, init)
-    >  result = init
-    >  for _, x in ipairs(l) do
-    >    result = f(result, x)
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp: original
-  filter:
-    >-- only for arrays
-    >function filter(l, f)
-    >  result = {}
-    >  for _, x in ipairs(l) do
-    >    if f(x) then
-    >      table.insert(result, x)
-    >    end
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp: original
-  find_index:
-    >function find_index(arr, x)
-    >  for n, y in ipairs(arr) do
-    >    if x == y then
-    >      return n
-    >    end
-    >  end
-    >end
-- __teliva_timestamp: original
-  trim:
-    >function trim(s)
-    >  return s:gsub('^%s*', ''):gsub('%s*$', '')
-    >end
-- __teliva_timestamp: original
-  split:
-    >function split(s, d)
-    >  result = {}
-    >  for match in (s..d):gmatch("(.-)"..d) do
-    >    table.insert(result, match);
-    >  end
-    >  return result
-    >end
-- __teliva_timestamp:
-    >Mon Feb 21 17:45:04 2022
-  sort_string:
-    >function sort_string(s)
-    >  tmp = {}
-    >  for i=1,#s do
-    >    table.insert(tmp, s[i])
-    >  end
-    >  table.sort(tmp)
-    >  local result = ''
-    >  for _, c in pairs(tmp) do
-    >    result = result..c
-    >  end
-    >  return result
-    >end
-    >
-    >function test_sort_string(s)
-    >  check_eq(sort_string(''), '', 'test_sort_string: empty')
-    >  check_eq(sort_string('ba'), 'ab', 'test_sort_string: non-empty')
-    >  check_eq(sort_string('abba'), 'aabb', 'test_sort_string: duplicates')
-    >end
-- __teliva_timestamp: original
-  append:
-    >-- concatenate list 'elems' into 'l', modifying 'l' in the process
-    >function append(l, elems)
-    >  for i=1,#elems do
-    >    l[#l+1] = elems[i]
-    >  end
-    >end
-- __teliva_timestamp: original
-  Window:
-    >Window = curses.stdscr()
-- __teliva_timestamp: original
-  render:
-    >function render(window)
-    >  window:clear()
-    >  -- draw stuff to screen here
-    >  window:attron(curses.A_BOLD)
-    >  window:mvaddstr(1, 5, "example app")
-    >  window:attrset(curses.A_NORMAL)
-    >  for i=0,15 do
-    >    window:attrset(curses.color_pair(i))
-    >    window:mvaddstr(3+i, 5, "========================")
-    >  end
-    >  window:refresh()
-    >end
 - __teliva_timestamp: original
   menu:
     >-- To show app-specific hotkeys in the menu bar, add hotkey/command
     >-- arrays of strings to the menu array.
     >menu = {}
 - __teliva_timestamp: original
-  update:
-    >function update(window)
-    >  local key = window:getch()
-    >  -- process key here
-    >end
-- __teliva_timestamp: original
-  init_colors:
-    >function init_colors()
-    >  for i=0,7 do
-    >    curses.init_pair(i, i, -1)
-    >  end
-    >  curses.init_pair(8, 7, 0)
-    >  curses.init_pair(9, 7, 1)
-    >  curses.init_pair(10, 7, 2)
-    >  curses.init_pair(11, 7, 3)
-    >  curses.init_pair(12, 7, 4)
-    >  curses.init_pair(13, 7, 5)
-    >  curses.init_pair(14, 7, 6)
-    >  curses.init_pair(15, -1, 15)
-    >end
-- __teliva_timestamp: original
-  main:
-    >function main()
-    >  init_colors()
-    >
-    >  while true do
-    >    render(Window)
-    >    update(Window)
-    >  end
-    >end
+  Window:
+    >Window = curses.stdscr()
 - __teliva_timestamp: original
   doc:blurb:
     >To show a brief description of the app on the 'big picture' screen, put the text in a special buffer called 'doc:blurb'.
diff --git a/template.tlv b/template.tlv
index 63210d1..4ec78b2 100644
--- a/template.tlv
+++ b/template.tlv
@@ -177,8 +177,7 @@
     >  end
     >  return result
     >end
-- __teliva_timestamp:
-    >Mon Feb 21 17:45:04 2022
+- __teliva_timestamp: original
   sort_letters:
     >function sort_letters(s)
     >  tmp = {}
@@ -220,64 +219,14 @@
     >    l[#l+1] = elems[i]
     >  end
     >end
-- __teliva_timestamp: original
-  Window:
-    >Window = curses.stdscr()
-- __teliva_timestamp: original
-  render:
-    >function render(window)
-    >  window:clear()
-    >  -- draw stuff to screen here
-    >  window:attron(curses.A_BOLD)
-    >  window:mvaddstr(1, 5, "example app")
-    >  window:attrset(curses.A_NORMAL)
-    >  for i=0,15 do
-    >    window:attrset(curses.color_pair(i))
-    >    window:mvaddstr(3+i, 5, "========================")
-    >  end
-    >  window:refresh()
-    >end
 - __teliva_timestamp: original
   menu:
     >-- To show app-specific hotkeys in the menu bar, add hotkey/command
     >-- arrays of strings to the menu array.
     >menu = {}
 - __teliva_timestamp: original
-  update:
-    >function update(window)
-    >  local key = window:getch()
-    >  -- process key here
-    >end
-- __teliva_timestamp: original
-  init_colors:
-    >function init_colors()
-    >  for i=0,7 do
-    >    curses.init_pair(i, i, -1)
-    >  end
-    >  curses.init_pair(8, 7, 0)
-    >  curses.init_pair(9, 7, 1)
-    >  curses.init_pair(10, 7, 2)
-    >  curses.init_pair(11, 7, 3)
-    >  curses.init_pair(12, 7, 4)
-    >  curses.init_pair(13, 7, 5)
-    >  curses.init_pair(14, 7, 6)
-    >  curses.init_pair(15, -1, 15)
-    >end
-- __teliva_timestamp: original
-  main:
-    >function main()
-    >  init_colors()
-    >
-    >  while true do
-    >    render(Window)
-    >    update(Window)
-    >  end
-    >end
-- __teliva_timestamp: original
-  doc:blurb:
-    >To show a brief description of the app on the 'big picture' screen, put the text in a special buffer called 'doc:blurb'.
-    >
-    >You can also override the default big picture screen entirely by creating a buffer called 'doc:main'.
+  Window:
+    >Window = curses.stdscr()
 - __teliva_timestamp: original
   window:
     >-- constructor for fake screen and window
@@ -346,8 +295,7 @@
     >  end
     >  return props
     >end
-- __teliva_timestamp:
-    >Thu Mar  3 22:04:15 2022
+- __teliva_timestamp: original
   check_screen:
     >function check_screen(window, contents, message)
     >  local x, y = 1, 1
@@ -433,3 +381,53 @@
     >    outfile:write(line)
     >  end
     >end
+- __teliva_timestamp: original
+  render:
+    >function render(window)
+    >  window:clear()
+    >  -- draw stuff to screen here
+    >  window:attron(curses.A_BOLD)
+    >  window:mvaddstr(1, 5, "example app")
+    >  window:attrset(curses.A_NORMAL)
+    >  for i=0,15 do
+    >    window:attrset(curses.color_pair(i))
+    >    window:mvaddstr(3+i, 5, "========================")
+    >  end
+    >  window:refresh()
+    >end
+- __teliva_timestamp: original
+  update:
+    >function update(window)
+    >  local key = window:getch()
+    >  -- process key here
+    >end
+- __teliva_timestamp: original
+  init_colors:
+    >function init_colors()
+    >  for i=0,7 do
+    >    curses.init_pair(i, i, -1)
+    >  end
+    >  curses.init_pair(8, 7, 0)
+    >  curses.init_pair(9, 7, 1)
+    >  curses.init_pair(10, 7, 2)
+    >  curses.init_pair(11, 7, 3)
+    >  curses.init_pair(12, 7, 4)
+    >  curses.init_pair(13, 7, 5)
+    >  curses.init_pair(14, 7, 6)
+    >  curses.init_pair(15, -1, 15)
+    >end
+- __teliva_timestamp: original
+  main:
+    >function main()
+    >  init_colors()
+    >
+    >  while true do
+    >    render(Window)
+    >    update(Window)
+    >  end
+    >end
+- __teliva_timestamp: original
+  doc:blurb:
+    >To show a brief description of the app on the 'big picture' screen, put the text in a special buffer called 'doc:blurb'.
+    >
+    >You can also override the default big picture screen entirely by creating a buffer called 'doc:main'.
diff --git a/toot-toot.tlv b/toot-toot.tlv
index 8d03654..66b0d9e 100644
--- a/toot-toot.tlv
+++ b/toot-toot.tlv
@@ -79,11 +79,11 @@
 - __teliva_timestamp: original
   check_eq:
     >function check_eq(x, expected, msg)
-    >  if x == expected then
+    >  if eq(x, expected) then
     >    Window:addch('.')
     >  else
     >    print('F - '..msg)
-    >    print('  expected '..tostring(expected)..' but got '..x)
+    >    print('  expected '..str(expected)..' but got '..str(x))
     >    teliva_num_test_failures = teliva_num_test_failures + 1
     >    -- overlay first test failure on editors
     >    if teliva_first_failure == nil then
@@ -91,6 +91,37 @@
     >    end
     >  end
     >end
+- __teliva_timestamp: original
+  eq:
+    >function eq(a, b)
+    >  if type(a) ~= type(b) then return false end
+    >  if type(a) == 'table' then
+    >    if #a ~= #b then return false end
+    >    for k, v in pairs(a) do
+    >      if b[k] ~= v then
+    >        return false
+    >      end
+    >      return true
+    >    end
+    >  end
+    >  return a == b
+    >end
+- __teliva_timestamp: original
+  str:
+    >-- smarter tostring
+    >-- slow; used only for debugging
+    >function str(x)
+    >  if type(x) == 'table' then
+    >    local result = ''
+    >    result = result..#x..'{'
+    >    for k, v in pairs(x) do
+    >      result = result..str(k)..'='..str(v)..', '
+    >    end
+    >    result = result..'}'
+    >    return result
+    >  end
+    >  return tostring(x)
+    >end
 - __teliva_timestamp: original
   map:
     >-- only for arrays
@@ -146,16 +177,18 @@
     >  end
     >  return result
     >end
-- __teliva_timestamp: original
-  Window:
-    >Window = curses.stdscr()
-    >curses.curs_set(0)  -- we'll simulate our own cursor
 - __teliva_timestamp: original
   menu:
+    >-- To show app-specific hotkeys in the menu bar, add hotkey/command
+    >-- arrays of strings to the menu array.
     >menu = {
     >  {'^k', 'clear'},
     >  {'^w', 'write prose to file "toot" (edit hotkey does NOT save)'},
     >}
+- __teliva_timestamp: original
+  Window:
+    >Window = curses.stdscr()
+    >curses.curs_set(0)  -- we'll simulate our own cursor
 - __teliva_timestamp: original
   main:
     >function main()
diff --git a/zet.tlv b/zet.tlv
index 7a718aa..6105fda 100644
--- a/zet.tlv
+++ b/zet.tlv
@@ -79,11 +79,11 @@
 - __teliva_timestamp: original
   check_eq:
     >function check_eq(x, expected, msg)
-    >  if x == expected then
+    >  if eq(x, expected) then
     >    Window:addch('.')
     >  else
     >    print('F - '..msg)
-    >    print('  expected '..tostring(expected)..' but got '..x)
+    >    print('  expected '..str(expected)..' but got '..str(x))
     >    teliva_num_test_failures = teliva_num_test_failures + 1
     >    -- overlay first test failure on editors
     >    if teliva_first_failure == nil then
@@ -91,6 +91,37 @@
     >    end
     >  end
     >end
+- __teliva_timestamp: original
+  eq:
+    >function eq(a, b)
+    >  if type(a) ~= type(b) then return false end
+    >  if type(a) == 'table' then
+    >    if #a ~= #b then return false end
+    >    for k, v in pairs(a) do
+    >      if b[k] ~= v then
+    >        return false
+    >      end
+    >      return true
+    >    end
+    >  end
+    >  return a == b
+    >end
+- __teliva_timestamp: original
+  str:
+    >-- smarter tostring
+    >-- slow; used only for debugging
+    >function str(x)
+    >  if type(x) == 'table' then
+    >    local result = ''
+    >    result = result..#x..'{'
+    >    for k, v in pairs(x) do
+    >      result = result..str(k)..'='..str(v)..', '
+    >    end
+    >    result = result..'}'
+    >    return result
+    >  end
+    >  return tostring(x)
+    >end
 - __teliva_timestamp: original
   map:
     >-- only for arrays
@@ -147,15 +178,47 @@
     >  return result
     >end
 - __teliva_timestamp: original
-  spaces:
-    >function spaces(n)
-    >  for i=1,n do
-    >    Window:addch(' ')
+  sort_letters:
+    >function sort_letters(s)
+    >  tmp = {}
+    >  for i=1,#s do
+    >    table.insert(tmp, s[i])
     >  end
+    >  table.sort(tmp)
+    >  local result = ''
+    >  for _, c in pairs(tmp) do
+    >    result = result..c
+    >  end
+    >  return result
+    >end
+    >
+    >function test_sort_letters(s)
+    >  check_eq(sort_letters(''), '', 'test_sort_letters: empty')
+    >  check_eq(sort_letters('ba'), 'ab', 'test_sort_letters: non-empty')
+    >  check_eq(sort_letters('abba'), 'aabb', 'test_sort_letters: duplicates')
     >end
 - __teliva_timestamp: original
-  Window:
-    >Window = curses.stdscr()
+  count_letters:
+    >function count_letters(s)
+    >  local result = {}
+    >  for i=1,string.len(s) do
+    >    local c = s[i]
+    >    if result[c] == nil then
+    >      result[c] = 1
+    >    else
+    >      result[c] = result[c] + 1
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  append:
+    >-- concatenate list 'elems' into 'l', modifying 'l' in the process
+    >function append(l, elems)
+    >  for i=1,#elems do
+    >    l[#l+1] = elems[i]
+    >  end
+    >end
 - __teliva_timestamp: original
   menu:
     >-- To show app-specific hotkeys in the menu bar, add hotkey/command
@@ -163,6 +226,170 @@
     >menu = {
     >  {'^e', 'edit'},
     >}
+- __teliva_timestamp: original
+  Window:
+    >Window = curses.stdscr()
+- __teliva_timestamp: original
+  window:
+    >-- constructor for fake screen and window
+    >-- call it like this:
+    >--   local w = window{
+    >--     kbd=kbd('abc'),
+    >--     scr=scr{h=5, w=4},
+    >--   }
+    >-- eventually it'll do everything a real ncurses window can
+    >function window(h)
+    >  h.__index = h
+    >  setmetatable(h, h)
+    >  h.__index = function(table, key)
+    >    return rawget(h, key)
+    >  end
+    >  h.getch = function(self)
+    >    return table.remove(h.kbd, 1)
+    >  end
+    >  h.addch = function(self, c)
+    >    local scr = self.scr
+    >    if scr.cursy <= scr.h then
+    >      scr[scr.cursy][scr.cursx] = c
+    >      scr.cursx = scr.cursx+1
+    >      if scr.cursx > scr.w then
+    >        scr.cursy = scr.cursy+1
+    >        scr.cursx = 1
+    >      end
+    >    end
+    >  end
+    >  h.addstr = function(self, s)
+    >    for i=1,string.len(s) do
+    >      self:addch(s[i])
+    >    end
+    >  end
+    >  h.mvaddch = function(self, y, x, c)
+    >    self.scr.cursy = y
+    >    self.scr.cursx = x
+    >    self.addch(c)
+    >  end
+    >  h.mvaddstr = function(self, y, x, s)
+    >    self.scr.cursy = y
+    >    self.scr.cursx = x
+    >    self:addstr(s)
+    >  end
+    >  return h
+    >end
+- __teliva_timestamp: original
+  kbd:
+    >function kbd(keys)
+    >  local result = {}
+    >  for i=1,string.len(keys) do
+    >    table.insert(result, keys[i])
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  scr:
+    >function scr(props)
+    >  props.cursx = 1
+    >  props.cursy = 1
+    >  for y=1,props.h do
+    >    props[y] = {}
+    >    for x=1,props.w do
+    >      props[y][x] = ' '
+    >    end
+    >  end
+    >  return props
+    >end
+- __teliva_timestamp: original
+  check_screen:
+    >function check_screen(window, contents, message)
+    >  local x, y = 1, 1
+    >  for i=1,string.len(contents) do
+    >    check_eq(contents[i], window.scr[y][x], message..'/'..y..','..x)
+    >    x = x+1
+    >    if x > window.scr.w then
+    >      y = y+1
+    >      x = 1
+    >    end
+    >  end
+    >end
+    >
+    >-- putting it all together, an example test of both keyboard and screen
+    >function test_check_screen()
+    >  local lines = {
+    >    c='123',
+    >    d='234',
+    >    a='345',
+    >    b='456',
+    >  }
+    >  local w = window{
+    >    kbd=kbd('abc'),
+    >    scr=scr{h=3, w=5},
+    >  }
+    >  local y = 1
+    >  while true do
+    >    local c = w:getch()
+    >    if c == nil then break end
+    >    w:mvaddstr(y, 1, lines[c])
+    >    y = y+1
+    >  end
+    >  check_screen(w, '345  '..
+    >                  '456  '..
+    >                  '123  ',
+    >              'test_check_screen')
+    >end
+- __teliva_timestamp: original
+  start_reading:
+    >-- primitive for reading files from a file system (or, later, network)
+    >-- returns a channel or nil on error
+    >-- read lines from the channel using :recv()
+    >-- recv() on the channel will indicate end of file.
+    >function start_reading(fs, filename)
+    >  local result = task.Channel:new()
+    >  local infile = io.open(filename)
+    >  if infile == nil then return nil end
+    >  task.spawn(reading_task, infile, result)
+    >  return result
+    >end
+    >
+    >function reading_task(infile, chanout)
+    >  for line in infile:lines() do
+    >    chanout:send(line)
+    >  end
+    >  chanout:send(nil)  -- eof
+    >end
+- __teliva_timestamp: original
+  start_writing:
+    >-- primitive for writing files to a file system (or, later, network)
+    >-- returns a channel or nil on error
+    >-- write to the channel using :send()
+    >-- indicate you're done writing by calling :close()
+    >-- file will not be externally visible until :close()
+    >function start_writing(fs, filename)
+    >  local result = task.Channel:new()
+    >  local initial_filename = os.tmpname()
+    >  local outfile = io.open(initial_filename, 'w')
+    >  if outfile == nil then return nil end
+    >  result.close = function()
+    >    result:send(nil)  -- end of file
+    >    outfile:close()
+    >    os.rename(initial_filename, filename)
+    >  end
+    >  task.spawn(writing_task, outfile, result)
+    >  return result
+    >end
+    >
+    >function writing_task(outfile, chanin)
+    >  while true do
+    >    local line = chanin:recv()
+    >    if line == nil then break end  -- end of file
+    >    outfile:write(line)
+    >  end
+    >end
+- __teliva_timestamp: original
+  spaces:
+    >function spaces(n)
+    >  for i=1,n do
+    >    Window:addch(' ')
+    >  end
+    >end
 - __teliva_timestamp: original
   init_colors:
     >function init_colors()