Spiral

spiral.hs

import Diagrams.AST
import Control.Arrow
import Data.List

main = outputImage "Foo.png" 800 800 image

image = Images $ Atop spiral background

spiral = Modifier (Changes [Align C, Foreground red, LineWidth 0]) $ Shape $ Path Closed $ Offsets poly

background = Modifier (Changes [Scale 1.5 1.5, Align C, Foreground white, LineWidth 0]) $ Shape Square

poly = drop 2 path ++ reverse (map (xx (*1.01)) path)

path = zipWith combine segments (cycle rotations)

segments = take 100 $ iterate (*0.9) 1

rotations = [(1,0),(0,-1),(-1,0),(0,1)]

combine (f) (a,b) = (f * a, f * b)

red = RGBA 1 0 0 1

white = RGBA 1 1 1 1

xx f = f *** f

shuffle x y = concat $ transpose [x, y]