5168d44c ​

input = fill #0 (fill #1 black) |> rect ((#2 - 2, #3 - 2, #2, #3), red) |> fold (λr. rect ((r.1, r.2, r.1, r.2), green)) #4
output = fill #0 (fill #1 black) |> rect (#5, red) |> fold (λr. rect ((r.1, r.2, r.1, r.2), green)) #6
(VInt, HInt, VInt, HInt, UList (VInt, HInt), (VInt, HInt, VInt, HInt), UList (VInt, HInt))
(7v, 13h, 5v, 3h, {(4v, 12h), (4v, 10h), (4v, 8h), (4v, 6h), (4v, 4h), (4v, 2h)}, (3v, 3h, 5v, 5h), {(4v, 12h), (4v, 10h), (4v, 8h), (4v, 6h), (4v, 2h), (4v, 4h)})
(13v, 7h, 6v, 6h, {(13v, 5h), (1v, 5h), (11v, 5h), (9v, 5h), (7v, 5h), (3v, 5h), (5v, 5h)}, (6v, 4h, 8v, 6h), {(13v, 5h), (1v, 5h), (11v, 5h), (9v, 5h), (5v, 5h), (3v, 5h), (7v, 5h)})
(7v, 7h, 4v, 4h, {(7v, 3h), (1v, 3h), (5v, 3h), (3v, 3h)}, (4v, 2h, 6v, 4h), {(7v, 3h), (1v, 3h), (3v, 3h), (5v, 3h)})
(7v, 17h, 6v, 10h, {(5v, 17h), (5v, 1h), (5v, 15h), (5v, 13h), (5v, 11h), (5v, 7h), (5v, 5h), (5v, 3h), (5v, 9h)}, (?, ?, ?, ?), ?)