ff72ca3e ​

input = fill #0 (fill #1 black) |> fold rect #2
output = fill #0 (fill #1 black) |> fold (λr. rect (r, red)) #3 |> fold (λr. rect ((r.1, r.2, r.1, r.2), grey)) #4 |> fold (λr. rect ((r.1, r.2, r.1, r.2), yellow)) #5
(VInt, HInt, UList ((VInt, HInt, VInt, HInt), Color), UList (VInt, HInt, VInt, HInt), UList (VInt, HInt), UList (VInt, HInt))
(12v, 10h, {((12v, 10h, 12v, 10h), grey), ((8v, 1h, 8v, 1h), grey), ((1v, 7h, 1v, 7h), grey), ((11v, 2h, 11v, 2h), grey), ((9v, 7h, 9v, 7h), yellow), ((6v, 5h, 6v, 5h), grey), ((5v, 2h, 5v, 2h), grey), ((4v, 9h, 4v, 9h), grey), ((3v, 4h, 3v, 4h), yellow)}, {(7v, 5h, 11v, 9h), (2v, 3h, 4v, 5h)}, {(12v, 10h), (8v, 1h), (1v, 7h), (11v, 2h), (6v, 5h), (5v, 2h), (4v, 9h)}, {(9v, 7h), (3v, 4h)})
(9v, 10h, {((4v, 5h, 4v, 5h), yellow), ((4v, 2h, 4v, 2h), grey)}, {(2v, 3h, 6v, 7h)}, {(4v, 2h)}, {(4v, 5h)})
(9v, 8h, {((4v, 4h, 4v, 4h), yellow), ((2v, 3h, 2v, 3h), grey)}, {(3v, 3h, 5v, 5h)}, {(2v, 3h)}, {(4v, 4h)})
(9v, 11h, {((6v, 5h, 6v, 5h), yellow), ((2v, 6h, 2v, 6h), grey)}, {(3v, 2h, 9v, 8h)}, {(2v, 6h)}, {(6v, 5h)})
(30v, 20h, {((28v, 16h, 28v, 16h), grey), ((28v, 2h, 28v, 2h), grey), ((26v, 6h, 26v, 6h), yellow), ((20v, 15h, 20v, 15h), grey), ((20v, 9h, 20v, 9h), grey), ((20v, 2h, 20v, 2h), grey), ((17v, 19h, 17v, 19h), grey), ((16v, 16h, 16v, 16h), yellow), ((16v, 11h, 16v, 11h), grey), ((12v, 4h, 12v, 4h), grey), ((8v, 15h, 8v, 15h), grey), ((6v, 7h, 6v, 7h), yellow), ((3v, 16h, 3v, 16h), grey)}, ?, ?, ?)