to spiral :w :a :x :c :ww if :c = 0 [stop] penwidth :ww color [255-:w*2 0 :w*2] lt :x fw :w pu bw :w rt :x fw :w pd rt :a spiral :w +1 :a :x+0.7 :c -1 :ww + 0.1 end reset spiral 1 30 10 90 1