from turtle import *

# Silver starter: combine a loop with a simple function.
repeats = 18
shape_size = 70
turn_angle = 360 / repeats
pen_colour = "magenta"
pen_thickness = 3

speed(0)
bgcolor("black")
pencolor(pen_colour)
pensize(pen_thickness)

def draw_shape():
    circle(shape_size)
    right(60)
    circle(shape_size / 2)

for i in range(repeats):
    draw_shape()
    right(turn_angle)

done()