A cercle of squares in Python ?

import turtle

def square(x):
    for i in range(4):
        turtle.forward(x)
        turtle.left(90)

turtle.speed(20)
window = turtle.Screen()
window.bgcolor("yellow")

for j in range(180):
    turtle.left(2)
    square(100)

window.exitonclick()

# program: A Cercle of Squares
# implementation in Python 3.x: A.-P. Gaspar