Sierpinski.hs

import Diagrams.Prelude
import Diagrams.Backend.SVG.CmdLine
import Data.Colour.SRGB

sierpinski :: Double -> Int -> Diagram B R2
sierpinski c 0 = triangle c 
sierpinski c k = 
    let d' = sierpinski c (k-1)
        l  = c * 2^(k-1) 
        z  = sqrt 3 / 2 * l / 3 
        ps = [(0,z*2),(-l/2,-z),(l/2,-z)] in
    position $ map (\p -> (p2 p,d')) ps

main :: IO ()
main = mainWith d where
    d c k = pad 1.1 $ sierpinski c k # lcA transparent # fc (sRGB 0.3 0.3 0.3)