RAINBOW WITH PYTHON

import turtle

sc=turtle.Screen()

pen=turtle.Turtle()

def semi_circle(col,rad,val):

  pen.color(col)

  pen.circle(rad,-180)

  pen.up()

  pen.setpos(val,0)

  pen.down()

  pen.right(180)

col=['violet','indigo','blue','green','yellow','orange','red']

sc.setup(600,600)

sc.bgcolor('black')

pen.right(90)

pen.width(10)

pen.speed(7)

for i in range(7):

  semi_circle(col[i],10*(i+8),-10*(i+1))

pen.hideturtle()