(define arr1 [1 2 3 4])
(define arr2 [5 6 7 8])
(define tree (cons arr1 arr2))
(define tree1 (cons tree tree))
(gc)
(check (and
(eq tree '([1 2 3 4] . [5 6 7 8]))
(eq (car tree1) '([1 2 3 4] . [5 6 7 8]))
(eq (cdr tree1) '([1 2 3 4] . [5 6 7 8]))))