diff --git a/main.tal b/main.tal
index 6e033af..4bf5feb 100644
--- a/main.tal
+++ b/main.tal
@@ -22,7 +22,11 @@
 ( constants )
 %PTN_WIDTH { #0003 } ( pattern width. a short )
 %PTN_LEN { #0010 } ( pattern length. a short )
+%SONG_WIDTH { #0004 } ( song width. a short )
+%SONG_LEN { #00ff } ( song length. a short )
 
+%TIMELINE_DISP_WIDTH { #0018 } ( width on the display of the timeline )
+%PATTERN_DISP_WIDTH { #0040 } ( width on the display of a pattern )
 ( devices )
 
 |00 @System     [ &vector $2 &wst      $1 &rst    $1 &pad   $4 &r      $2 &g     $2 &b      $2 ]
@@ -73,12 +77,12 @@
 ( for the sake of testing, play pattern 0-3 on ch 0-3 )
 #00 .Channel0/pattern-index STZ
 .Channel0/pattern-index LDZ .Channel0/pattern-addr ;alloc-load-pattern JSR2
-#01 .Channel1/pattern-index STZ
+( #01 .Channel1/pattern-index STZ
 .Channel1/pattern-index LDZ .Channel1/pattern-addr ;alloc-load-pattern JSR2
 #02 .Channel2/pattern-index STZ
 .Channel2/pattern-index LDZ .Channel2/pattern-addr ;alloc-load-pattern JSR2
 #03 .Channel3/pattern-index STZ
-.Channel3/pattern-index LDZ .Channel3/pattern-addr ;alloc-load-pattern JSR2
+.Channel3/pattern-index LDZ .Channel3/pattern-addr ;alloc-load-pattern JSR2 )
 
 ( init editor to pattern 0 )
 #00 .Edit/pattern-index STZ
@@ -341,10 +345,6 @@ RTN
 
 ( draw-pattern-line draws a single line in a pattern )
 @draw-pattern-line ( addr )
-	.Draw/row LDZ ;draw-byte JSR2 ( draw the row number )
-	;line .Screen/addr DEO2
-	#21 .Screen/color DEO
-	.Screen/x DEI2 #0008 ADD2 .Screen/x DEO2 ( move right a sprite )
 	#00 .Draw/col STZ
 	&loop
 		#00 .Draw/col LDZ NEQ ,&else JCN ( if it's not the note value, draw a byte )
@@ -364,15 +364,30 @@ RTN
 @draw-pattern ( addr )
 	#00 .Draw/row STZ
 	&loop
-		.Draw/pattern-y LDZ2 .Screen/x DEO2
+		.Screen/x DEI2 STH2
+(		.Draw/pattern-y LDZ2 .Screen/x DEO2 )
 		DUP2 ;draw-pattern-line JSR2
 		.Screen/y DEI2 #0008 ADD2 .Screen/y DEO2 ( add spacing between rows )
+		STHr2 .Screen/x DEO2 ( reset X )
 		PTN_WIDTH ADD2 ( get the next byte in the pattern )
 		#01 .Draw/row LDZ ADD .Draw/row STZ
 		.Draw/row LDZ PTN_LEN LOB NEQ ,&loop JCN
 	POP2 ( remove final address from stack )
 RTN
 
+@draw-timeline ( draws numeric timeline to the side of patterns )
+	#00 .Draw/row STZ
+	&loop
+		.Screen/x DEI2 STH2
+		.Draw/row LDZ ;draw-byte JSR2 ( draw the row number )
+		;line .Screen/addr DEO2
+		#21 .Screen/color DEO
+		.Screen/y DEI2 #0008 ADD2 .Screen/y DEO2 ( add spacing between rows )
+		STHr2 .Screen/x DEO2 ( reset X )
+		#01 .Draw/row LDZ ADD .Draw/row STZ
+	.Draw/row LDZ PTN_LEN LOB NEQ ,&loop JCN
+RTN
+
 @draw-playhead 
 	( clear previous playhead )
 	.Draw/playhead-y LDZ2 .Screen/y DEO2
@@ -400,10 +415,15 @@ RTN
 	;draw-playhead JSR2
 	#0000 .Screen/x DEO2
 	#0000 .Screen/y DEO2
-	.Edit/pattern-index LDZ ;draw-byte JSR2
 	.Draw/pattern-x LDZ2 .Screen/x DEO2
 	.Draw/pattern-y LDZ2 .Screen/y DEO2
-	.Edit/pattern-addr LDZ2 ;draw-pattern JSR2
+	;draw-timeline JSR2
+	.Draw/pattern-x LDZ2 TIMELINE_DISP_WIDTH ADD2 .Screen/x DEO2 ( draw pattern after timeline )
+	.Draw/pattern-y LDZ2 .Screen/y DEO2
+	.Channel0/pattern-addr LDZ2 ;draw-pattern JSR2
+	.Draw/pattern-y LDZ2 .Screen/y DEO2
+	.Draw/pattern-x LDZ2 PATTERN_DISP_WIDTH TIMELINE_DISP_WIDTH .Draw/pattern-hspacing LDZ2 ADD2 ADD2 ADD2 .Screen/x DEO2
+	.Channel0/pattern-addr LDZ2 ;draw-pattern JSR2
 	;draw-free-mem JSR2
 RTN
 
@@ -420,6 +440,7 @@ RTN
 	POPr
 RTN
 
+(
 @on-step ( whenever a pattern step should be played )
 
 	PTN_LEN .Playback/position LDZ2 NEQ2 ,&continue JCN ( if we're at the end of the pattern, reset the counter )
@@ -437,6 +458,19 @@ RTN
 	#0001 .Playback/position LDZ2 ADD2 .Playback/position STZ2
 	;draw-playhead JSR2 ( update the playhead position )
 RTN 
+)
+
+@on-step 
+	PTN_LEN .Playback/position LDZ2 NEQ2 ,&continue JCN
+	( PATTERN SWITCHING CODE GOES HERE )
+	.Channel0/pattern-index LDZ #01 ADD DUP .Channel0/pattern-index STZ
+	.Channel0 ;alloc-load-pattern JSR2
+	#0000 .Playback/position STZ2
+	&continue 
+	.Playback/position LDZ2 PTN_WIDTH MUL2 .Channel0/pattern-addr LDZ2 ADD2
+	.Audio0 ;play-line JSR2
+	#0001 .Playback/position LDZ2 ADD2 .Playback/position STZ2
+RTN
 
 @draw-cursor ( -- )
 	
@@ -527,6 +561,7 @@ BRK
   an ff in the note column of the pattern will kill the existing note without starting a new one (this is the tracker "box" note) )
 
 @data ( start of data )
+@song $3fc ( $ff * 4, 256 lines on 4 channels )
 @pattern_table :ptn0 :ptn1 :ptn2 :ptn3 ( pattern table. Contains the addresses of patterns )
 @pattern_pointer :pointer-start ( pattern pointer. Points to where the next pattern will be written in memory )
 @ptn0