(define (square-tree tree) (tree-map square tree))
(define (tree-map square tree)
(map (lambda (tree)
(if (pair? tree)
(tree-map square tree)
(square tree)))
tree))
(define square (lambda (x) (* x x)))
(define (square-tree tree) (tree-map square tree))
(define (tree-map square tree)
(map (lambda (tree)
(if (pair? tree)
(tree-map square tree)
(square tree)))
tree))
(define square (lambda (x) (* x x)))