diff --git a/mceval/amb-fathers-daughters.rkt b/mceval/amb-fathers-daughters.rkt
index f8057a7..9164a6f 100644
--- a/mceval/amb-fathers-daughters.rkt
+++ b/mceval/amb-fathers-daughters.rkt
@@ -1,97 +1,22 @@
 ;; Exercise 4.42
 
 (define (fathers-daughters)
-  (let ((moore 'mary)
-        (hood 'melissa)
-        (downing (amb 'gabrielle 'lorna 'rosalind))
-        (hall (amb 'gabrielle 'lorna))
-        (parker (amb 'gabrielle 'lorna 'rosalind)))
-    (require (distinct? (list downing hall parker)))
-    ())
-  )
 
-(define (fathers-daughers)
-  (let ((mary 'moore)
-        (melissa 'hood)
-        (gabrielle (amb 'downing 'hall 'parker))
-        (lorna (amb 'downing 'hall 'parker))
-        (rosalind (amb 'downing 'hall 'parker)))
-    (require (distinct? (list gabrielle lorna rosalind)))
-    (require (gabrielle ))))
-
-(define (daughter father) (car father))
-(define (yacht father) (cadr father))
-(define (father daugher yacht) (list daugher yacht))
-
-(define (fathers-daughters)
-  (let ((moore (father 'mary 'lorna))
-        (hood (father 'melissa 'gabrielle))
-        (downing (father (amb 'gabrielle 'lorna 'rosalind) 'melissa))
-        (hall (father (amb 'gabrielle 'lorna) 'rosalind))
-        (parker (father (amb 'gabrielle 'lorna 'rosalind) (amb 'mary 'melissa))))
-    (require (distinct? (list (daughter downing) (daughter hall) (daughter parker))))
-    (require (distinct? (list (yacht downing) (yacht hall) (yacht parker))))
-    (require (= (yacht )(daughter parker)))))  ;; TODO
-
-
-(define (caar x) (car (car x)))
-
-(define (assoc key records)
-  (cond ((null? records) false)
-        ((equal? key (caar records)) (car records))
-        (else (assoc key (cdr records)))))
-
-(define (fathers-daughters)
-  (let ((yachts '((moore lorna)
-                  (hood gabrielle)
-                  (downing melissa)
-                  (hall rosalind)
-                  (parker mary)))
-        (moore 'mary)
-        (hood 'melissa)
-        (downing (amb 'lorna 'gabrielle 'rosalind))
-        (hall (amb 'lorna 'gabrielle))
-        (parker (amb 'lorna 'gabrielle 'rosalind))
-        (lorna (amb 'downing 'hall 'parker))
-        (gabrielle (amb 'downing 'hall 'parker))
-        (melissa 'hood)
-        (rosalind (amb 'downing 'parker))
-        (mary 'moore))
-    (require (distinct? (list lorna gabrielle rosalind
-                              downing hall parker)))
-    (require (eq? (car (cdr (assoc gabrielle yachts))) parker))
-    (list (list 'mary mary)
-          (list 'rosalind rosalind)
-          (list 'melissa melissa)
-          (list 'gabrielle gabrielle)
-          (list 'lorna lorna))))
-
-
-(define (caar x) (car (car x)))
-(define (cadr x) (car (cdr x)))
-(define (caddr x) (car (cdr (cdr x))))
-
-(define (assq key records)
-  (cond ((null? records) false)
-        ((eq? key (caar records)) (car records))
-        (else (assq key (cdr records)))))
-
-(define (fathers-daughters)
-
-  (define daughter caddr)
+  (define father car)
   (define yacht cadr)
+  (define daughter caddr)
   
-  (define (lookup-daughter father fathers)
-    (daughter (assq father fathers)))
+  (define (lookup-daughter f fathers)
+    (daughter (assq f fathers)))
 
-  (define (lookup-yacht father fathers)
-    (yacht (assq father fathers)))
+  (define (lookup-yacht f fathers)
+    (yacht (assq f fathers)))
   
-  (define (lookup-father daughter fathers)
+  (define (lookup-father d fathers)
     (cond ((null? fathers) false)
-          ((eq? daughter (daughter (car fathers)))
+          ((eq? d (daughter (car fathers)))
            (car (car fathers)))
-          (else (father daughter (cdr fathers)))))
+          (else (lookup-father d (cdr fathers)))))
 
   ;; Optimisation.  Put everything we already know in a table.  Each
   ;; row is father, yacht, daughter.
@@ -99,7 +24,7 @@
     (list
      (list 'moore 'lorna 'mary)
      (list 'hood 'gabrielle 'melissa)
-     (list 'downing 'melissa (amb 'lorna 'gabriella 'rosalind))
+     (list 'downing 'melissa (amb 'lorna 'gabrielle 'rosalind))
      (list 'hall 'rosalind (amb 'lorna 'gabrielle))
      (list 'parker 'mary (amb 'lorna 'gabrielle 'rosalind))))
 
@@ -109,7 +34,7 @@
                             (lookup-daughter 'hall fathers)
                             (lookup-daughter 'parker fathers))))
   ;; Gabrielle's father owns the yacht named after parker's daughter
-  (require (eq? (lookup-yacht (lookup-father 'gabrielle fathers))
+  (require (eq? (lookup-yacht (lookup-father 'gabrielle fathers) fathers)
                 (lookup-daughter 'parker fathers)))
   fathers)
 
diff --git a/mceval/environment.rkt b/mceval/environment.rkt
index b3b99cd..a2be090 100644
--- a/mceval/environment.rkt
+++ b/mceval/environment.rkt
@@ -1,5 +1,7 @@
 #lang sicp
 
+(#%require racket/trace)
+
 (#%provide lookup-variable-value
            set-variable-value!
            define-variable!
@@ -156,6 +158,8 @@
 (define primitive-procedures
   (list (list 'car car)
         (list 'cdr cdr)
+        (list 'cadr cadr)
+        (list 'caddr caddr)
         (list 'cons cons)
         (list 'null? null?)
         (list 'list list)
@@ -182,6 +186,8 @@
         (list 'integer? integer?)
         (list 'sqrt sqrt)
         (list 'eq? eq?)
+        (list 'assq assq)
+        (list 'equal? equal?)
         (list 'newline newline)
         (list 'display display)
         ))