72a961c9 ​

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