5521c0d9 ​

input = fill 15v (fill 15h black) |> rect ((#0, #1, 15v, #2), red) |> rect ((#3, #4, 15v, #5), yellow) |> rect ((#6, #7, 15v, #8), blue)
output = fill 15v (fill 15h black) |> fold (λr. rect ((r, map (λr. (r, #14, #9 - 1, #15)) (map (λr. (r, #13 - 1)) #10), #9 - 1, map (λr. (r, #18, #9 - 1, #19)) (map (λr. (r, #17 - 1)) #11)), red)) #9 |> fold (λr. rect ((r, #14, #13 - 1, #15), yellow)) #10 |> fold (λr. rect ((r, #18, #17 - 1, #19), blue)) #11
(VInt, HInt, HInt, VInt, HInt, HInt, VInt, HInt, HInt, UList VInt, UList VInt, UList VInt)
(14v, 5h, 8h, 12v, 10h, 13h, 12v, 2h, 3h, {12v}, {8v}, {8v})
(11v, 12h, 13h, 10v, 2h, 5h, 14v, 8h, 9h, {6v}, {4v}, {12v})
(15v, 2h, 5h, 13v, 12h, 13h, 12v, 8h, 8h, {14v}, {10v}, {8v})
(9v, 1h, 4h, 10v, 6h, 8h, 13v, 11h, 15h, ?, ?, ?)