判斷式2

//設定畫布大小
size 400 400
//使運算速度加快
fast
//設定背景
paper 100
//設計一個實心圓形圖形
command circlepixels cx cy dx dy
{
line (cx+dx) (cy+dy) (cx+dx) (cy-dy)
line (cx-dx) (cy+dy) (cx-dx) (cy-dy)
line (cx-dy) (cy+dx) (cx+dy) (cy+dx)
line (cx-dy) (cy-dx) (cx+dy) (cy-dx)
}
command circle cx cy radius
{
set x 0
set y radius
set d (1-radius)
//circlepixels cx cy x y
// 707/1000 approximates square root of 0.5 = cos(45)
repeat x 0 (radius*400/1000)
{
set tempd d
smaller? tempd 1
{
set d (d+(2*x)+30)
} notsmaller? tempd 0
{
set d (d+(2*(x-y))+50)
set y (y-10)
}
circlepixels cx cy x y
}
}

forever
{
pen
circle (/6)
}