Code Sketch

clear()
setBackground(green)
setFillColor(green)
setSpeed(fast)
    repeat(20){
        circle(60)
        right(50)
    }
right(18)
invisible
 repeat(20){
        circle(50)
        right(50)
    }
right(18)
invisible
 repeat(20){
        circle(50)
        right(50)
    }
right(18)
invisible
 repeat(20){
        circle(40)
        right(50)
    }
right(18)
invisible
 repeat(20){
        circle(40)
        right(50)
    }
right(18)
invisible