9ddd00f0 ​

input = fill #0 (fill #1 black) |> fold (λr. rect (r, #2)) #3 |> fold (λr. rect ((r.1, r.2, r.1, r.2), black)) #4
output = fill #0 (fill #1 black) |> fold (λr. rect ((r.1, #5, r.2, #1), #2)) #6 |> fold (λr. rect ((r.1, 1h, r.2, #7), #2)) #8 |> fold (λr. rect ((r.1, #9, r.2, #10), #2)) #11 |> fold (λr. rect ((r, #1, r, #1), black)) #12 |> fold (λr. rect ((r, 1h, r, 1h), black)) #13 |> fold (λr. rect ((r, #14, r, #15), black)) #16
(VInt, HInt, Color, UList (VInt, HInt, VInt, HInt), UList (VInt, HInt), HInt, UList (VInt, VInt), HInt, UList (VInt, VInt), HInt, HInt, UList (VInt, VInt), UList VInt, UList VInt, HInt, HInt, UList VInt)
(11v, 11h, red, {(9v, 9h, 11v, 11h), (9v, 5h, 11v, 7h), (1v, 9h, 3v, 11h), (1v, 5h, 3v, 7h), (5v, 5h, 7v, 7h)}, {(11v, 11h), (11v, 6h), (1v, 11h), (1v, 6h), (6v, 6h)}, 9h, {(9v, 11v), (5v, 7v), (1v, 3v)}, 3h, {(9v, 11v), (5v, 7v), (1v, 3v)}, 5h, 7h, {(9v, 11v), (1v, 3v), (5v, 7v)}, {11v, 6v, 1v}, {11v, 6v, 1v}, 6h, 6h, {11v, 1v, 6v})
(5v, 5h, teal, {(4v, 4h, 5v, 5h), (4v, 1h, 5v, 2h)}, {(5v, 5h), (5v, 1h)}, 4h, {(4v, 5v)}, 2h, {(4v, 5v), (1v, 2v)}, 4h, 5h, {(1v, 2v)}, {5v}, {5v, 1v}, 5h, 5h, {1v})
(19v, 19h, blue, {(16v, 6h, 19v, 9h), (16v, 1h, 19v, 4h), (6v, 16h, 9v, 19h), (1v, 11h, 4v, 14h), (11v, 6h, 14v, 9h), (6v, 11h, 9v, 14h), (6v, 6h, 9v, 9h)}, {(19v, 7h), (19v, 1h), (7v, 19h), (1v, 13h), (13v, 7h), (7v, 13h), (7v, 7h)}, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)