50cb2852 ​

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