pen 0 set a 2 repeat b (a*5) (a*20) { paper (100-b) line b b (50+b/3) (70+b/4) } repeat a 3 5 { repeat b ((a-1)*20) (a*5) { paper (100-b) line b b (50+b/3) (70+b/4) } repeat b (a*5) (a*20) { paper (100-b) line b b (50+b/3) (70+b/4) } }