94414823 ​

input = fill 10v (fill 10h black) |> rect ((3v, 3h, 8v, 8h), grey) |> rect ((#0, #1, #0, #1), #2) |> rect ((#3, #4, #3, #4), #5) |> rect ((4v, 4h, 7v, 7h), black)
output = fill 10v (fill 10h black) |> rect ((3v, 3h, 8v, 8h), grey) |> fold (λr. rect (r, #6)) #7 |> fold (λr. rect (r, #8)) #9
(VInt, HInt, Color, VInt, HInt, Color, Color, UList (VInt, HInt, VInt, HInt), Color, UList (VInt, HInt, VInt, HInt))
(2v, 9h, teal, 2v, 2h, yellow, teal, {(2v, 9h, 2v, 9h), (6v, 4h, 7v, 5h), (4v, 6h, 5v, 7h)}, yellow, {(2v, 2h, 2v, 2h), (6v, 6h, 7v, 7h), (4v, 4h, 5v, 5h)})
(9v, 9h, orange, 2v, 9h, fuschia, fuschia, {(2v, 9h, 2v, 9h), (6v, 4h, 7v, 5h), (4v, 6h, 5v, 7h)}, orange, {(9v, 9h, 9v, 9h), (6v, 6h, 7v, 7h), (4v, 4h, 5v, 5h)})
(9v, 2h, red, 2v, 2h, green, red, {(9v, 2h, 9v, 2h), (6v, 4h, 7v, 5h), (4v, 6h, 5v, 7h)}, green, {(2v, 2h, 2v, 2h), (6v, 6h, 7v, 7h), (4v, 4h, 5v, 5h)})
(9v, 9h, blue, 9v, 2h, brown, ?, ?, ?, ?)