turtle triangle fun
Just Wrote this piece of code. First just copy-paste the code, run and have fun. Then try to write it yourself and have more fun. :)

import turtle
def draw_triangle(side_length, depth):
if depth == 0:
return
counter = 0
while counter < 3:
counter += 1
brad.forward(side_length/2)
if depth > 1:
brad.left(120)
draw_triangle(side_length/2, depth-1)
brad.forward(side_length/2)
brad.right(120)
brad.left(240)
if __name__ == "__main__":
window = turtle.Screen()
window.bgcolor("white")
brad = turtle.Turtle()
brad.shape("turtle")
brad.color("green", "green")
brad.speed(5)
brad.begin_fill()
brad.right(120)
brad.forward(128)
brad.left(120)
brad.forward(256)
brad.left(120)
brad.forward(256)
brad.left(120)
brad.forward(128)
brad.left(120)
brad.end_fill()
brad.color("green", "white")
brad.begin_fill()
draw_triangle(128, 3)
brad.end_fill()
window.exitonclick()

Comments
File "turtle.py", line 23, in
window = turtle.Screen()
AttributeError: 'module' object has no attribute 'Screen'
What python version you use? I tried 2.7.6 and 3.4 (linuxmint).