11852cab ​

input = fill 10v (fill 10h black) |> fold (fold rect) #0
output = fill 10v (fill 10h black) |> fold (fold rect) #1
(OList UList ((VInt, HInt, VInt, HInt), Color), OList UList ((VInt, HInt, VInt, HInt), Color))
([{((3v, 4h, 5v, 6h), red)}, {((3v, 5h, 5v, 5h), black)}, {((4v, 4h, 4v, 6h), black)}, {((6v, 5h, 6v, 5h), teal), ((4v, 7h, 4v, 7h), teal), ((4v, 3h, 4v, 3h), teal), ((2v, 5h, 2v, 5h), teal), ((2v, 3h, 2v, 3h), green), ((4v, 5h, 4v, 5h), green)}], [{((3v, 4h, 5v, 6h), red)}, {((3v, 5h, 5v, 5h), black)}, {((4v, 4h, 4v, 6h), black)}, {((6v, 7h, 6v, 7h), green), ((6v, 5h, 6v, 5h), teal), ((6v, 3h, 6v, 3h), green), ((4v, 7h, 4v, 7h), teal), ((4v, 3h, 4v, 3h), teal), ((2v, 7h, 2v, 7h), green), ((2v, 5h, 2v, 5h), teal), ((2v, 3h, 2v, 3h), green), ((4v, 5h, 4v, 5h), green)}])
([{((4v, 4h, 6v, 6h), yellow)}, {((4v, 5h, 6v, 5h), black)}, {((5v, 4h, 5v, 6h), black)}, {((7v, 5h, 7v, 5h), green), ((5v, 7h, 5v, 7h), green), ((5v, 3h, 5v, 3h), green), ((3v, 5h, 3v, 5h), green), ((3v, 3h, 3v, 3h), red), ((5v, 5h, 5v, 5h), yellow)}], [{((4v, 4h, 6v, 6h), yellow)}, {((4v, 5h, 6v, 5h), black)}, {((5v, 4h, 5v, 6h), black)}, {((7v, 7h, 7v, 7h), red), ((7v, 5h, 7v, 5h), green), ((7v, 3h, 7v, 3h), red), ((5v, 7h, 5v, 7h), green), ((5v, 3h, 5v, 3h), green), ((3v, 7h, 3v, 7h), red), ((3v, 5h, 3v, 5h), green), ((3v, 3h, 3v, 3h), red), ((5v, 5h, 5v, 5h), yellow)}])
([{((6v, 8h, 6v, 8h), teal), ((6v, 6h, 6v, 6h), teal), ((6v, 4h, 6v, 4h), teal), ((4v, 8h, 4v, 8h), teal), ((4v, 6h, 4v, 6h), blue), ((4v, 4h, 4v, 4h), teal), ((3v, 5h, 3v, 5h), yellow), ((2v, 8h, 2v, 8h), teal), ((2v, 6h, 2v, 6h), teal), ((2v, 4h, 2v, 4h), teal)}], [{((3v, 5h, 5v, 7h), yellow)}, {((3v, 6h, 5v, 6h), black)}, {((4v, 5h, 4v, 7h), black)}, {((6v, 8h, 6v, 8h), teal), ((6v, 6h, 6v, 6h), teal), ((6v, 4h, 6v, 4h), teal), ((4v, 8h, 4v, 8h), teal), ((4v, 4h, 4v, 4h), teal), ((2v, 8h, 2v, 8h), teal), ((2v, 6h, 2v, 6h), teal), ((2v, 4h, 2v, 4h), teal), ((4v, 6h, 4v, 6h), blue)}])
([{((4v, 3h, 4v, 5h), red)}, {((7v, 6h, 7v, 6h), blue), ((7v, 2h, 7v, 2h), blue), ((6v, 5h, 6v, 5h), red), ((6v, 3h, 6v, 3h), red), ((5v, 4h, 5v, 4h), blue), ((3v, 6h, 3v, 6h), blue), ((3v, 4h, 3v, 4h), yellow), ((3v, 2h, 3v, 2h), blue), ((4v, 4h, 4v, 4h), black)}], ?)