21f83797 ​

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