clear()
setBackgroundH(pink, blue)
setSpeed(fast)
setPenColor(gray)
setFillColor(black)
circle(100)
setFillColor(white)
circle(90)
setFillColor(black)
circle(80)
setFillColor(white)
circle(70)
setFillColor(black)
circle(60)
setFillColor(white)
circle(50)
setFillColor(black)
circle(40)
setFillColor(white)
circle(30)
setFillColor(black)
circle(20)
setFillColor(white)
circle(10)
setFillColor(black)
circle(5)
invisible()