332efdb3 ​

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