ae3edfdc ​

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