paper 0
pen 100
command box a b
{
set c (a+20)
set d (b+20)
line a b c b
line c b c d
line c d a d
line a d a b
}
box 38 88
box 30 35
box 50 42
box 5 5
box 30 55
box 15 27
box 2 50
box 23 52
box 20 75
box 42 70
box 40 50
box 37 30
box 20 0
box 50 5
box 45 30
box 38 15
box 42 3
box 83 46
box 50 86
box 46 76
box 46 60
repeat f 0 100
{
box 70 (3*f)
box 65 (5*f)
box 90 f
box 68 (7*f)
box 60 (10*f)
box 57 (15*f)
box 75 (5*f)
box 80 (2*f)
}