1 (define (list->tree elements)
2   (car (partial-tree elements (length elements))))
3 
4 (define (partial-tree elts n)
5   (if (= n 0)
6       (cons '() elts)
7       (let ((left-size (quotient (- n 1) 2)))
8 	(let ((left-result (partial-tree elts left-size)))
9 	  (let ((left-tree (car left-result))
10 		(non-left-elts (cdr left-result))
11 		(right-size (- n (+ left-size 1))))
12 	    (let ((this-entry (car non-left-elts))
13 		  (right-result (partial-tree (cdr non-left-elts) right-size)))
14 	      (let ((right-tree (car right-result))
15 		    (remaining-elts (cdr right-result)))
16 		(cons (make-tree this-entry left-tree right-tree)
17 		      remaining-elts))))))))