A tessellation inspired by the Alhambra. The exercise only made me appreciate the original piece of art more.

tessel.py

from turtle import *

WIDTH = 1280
HEIGHT = 800
RADIUS = 50


def init():
    setup(WIDTH, HEIGHT)
    setworldcoordinates(0, 0, WIDTH, HEIGHT)
    hideturtle()
    tracer(0, 0)


def draw_one(x, y, radius):
    up()
    width(1)
    goto(x, y)
    forward(radius)
    right(90)
    down()
    forward(WIDTH)
    backward(2 * WIDTH)
    left(90)


def outline(x, y, w, outer_radius, outline_length):
    def draw(*turn):
        unwind = 0
        for angle in turn:
            unwind -= angle
            left(angle)
            forward(outline_length)
        left(unwind)

    up()
    width(w)
    goto(x, y)
    forward(outer_radius)
    down()
    draw(60, 90, -60, 90, -60, 90)


init()
shift = False
for y in range(0, HEIGHT, int(3.46 * RADIUS)):
    for x in range(0 if not shift else 2 * RADIUS, WIDTH, 4 * RADIUS):
        for i in range(12):
            draw_one(x, y, RADIUS)
            right(30)
        for i in range(4):
            outline(x, y, 4, 1.15 * RADIUS, 0.422222 * RADIUS)
            if shift:
                outline(x, y, 3, 0.85 * RADIUS, 0.31 * RADIUS)
            right(90)
    shift = not shift
update()
done()