7ddcd7ec ​

let c: Color
let y: Int
let x: Int
let ds: UList (Int, Int)

let input = fill 10 (fill 10 black)
  |> rect ((y, x, y + 1, x + 1), c)
  |> fold (λ(dy, dx). point (y + (dy * 3 + 1) / 2, x + (dx * 3 + 1) / 2) c) ds

let output = fill 10 (fill 10 black)
  |> rect ((y, x, y + 1, x + 1), c)
  |> fold (λ(dy, dx). rep1 (dy, dx) [(y + (dy * 3 + 1) / 2, x + (dx * 3 + 1) / 2, c)]) ds