516b51b7 ​

input = fill #0 (fill #1 black) |> fold (λr. rect (r, blue)) #2
output = fill #0 (fill #1 black) |> fold (fold rect) #3
(VInt, HInt, UList (VInt, HInt, VInt, HInt), OList UList ((VInt, HInt, VInt, HInt), Color))
(12v, 11h, {(7v, 3h, 12v, 7h), (2v, 8h, 4v, 10h), (2v, 2h, 5v, 5h)}, [{((7v, 3h, 12v, 7h), blue)}, {((8v, 4h, 11v, 6h), red), ((2v, 8h, 4v, 10h), blue), ((2v, 2h, 5v, 5h), blue)}, {((9v, 5h, 10v, 5h), green), ((3v, 9h, 3v, 9h), red), ((3v, 3h, 4v, 4h), red)}])
(12v, 13h, {(10v, 9h, 12v, 11h), (2v, 2h, 8v, 9h)}, [{((2v, 2h, 8v, 9h), blue)}, {((3v, 3h, 7v, 8h), red)}, {((10v, 9h, 12v, 11h), blue), ((4v, 4h, 6v, 7h), green)}, {((11v, 10h, 11v, 10h), red), ((5v, 5h, 5v, 6h), red)}])
(15v, 14h, {(11v, 5h, 15v, 11h), (2v, 3h, 9v, 10h)}, [{((2v, 3h, 9v, 10h), blue)}, {((11v, 5h, 15v, 11h), blue), ((3v, 4h, 8v, 9h), red)}, {((12v, 6h, 14v, 10h), red), ((4v, 5h, 7v, 8h), green)}, {((13v, 7h, 13v, 9h), green), ((5v, 6h, 6v, 7h), red)}])
(15v, 17h, {(8v, 10h, 15v, 16h), (1v, 3h, 6v, 13h), (10v, 2h, 12v, 6h)}, ?)