espiral.py

import turtle, colorsys, math

t = turtle.Turtle()
t.pensize(4); t.right(90); t.speed(0)
n, j, i, p = 19, 1, 1, (5 ** 0.5 - 1) / 2
for k in range(n):
    r, g, b = colorsys.hls_to_rgb(p * k % 1, p, 1)
    t.color('white', (r, g, b))
    t.begin_fill()
    for k in range(4):
        t.forward(i)
        t.left(90)
    t.end_fill()
    t.circle(i, 90)
    i, j = j, i + j