10fcaaa3 ​

let g: Grid monochrome

let input =
  g

let output =
  gstamp (λc. λx. λy. stack (draw ((x - 1) (y - 1) lean)
                          :: draw ((x - 1) (y + 1) lean)
                          :: draw ((x + 1) (y - 1) lean)
                          :: draw ((x + 1) (y + 1) lean)
                          :: [])) (hrep (vrep g 2) 2) g