# Find the largest palindrome made from the product of two 3-digit numbers.
# https://projecteuler.net/problem=4

[ digits dup rev eq? ] [ palin? ] def

[ 999 999 [ ] ]

[...[ a b ps ]::
    [
        [ a b * palin? ] [ [ ] a push
                               b 1 - push
                               ps a b * push push ]
        # Assuming both factors will be in the 900s...
        [ b 900 eq? ]    [ [ ] a 1 - push
                               999 push
                               ps push ]
        [ otherwise ]    [ [ ] a push
                               b 1 - push
                               ps push ]
    ] ?
] [ palin-once ] def

[ palin-once ] 10000 times

last maximum println