af24b4cc ​

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