3-12.py

#!/usr/bin/env python
__author__ = 'Ernest'

import turtle

wn = turtle.Screen()
wn.bgcolor("lightgreen")    # sets the background colour
wn.title("Hello, Ernest!")  # set the window title

tess = turtle.Turtle()
tess.color("Blue")          # change the pen colour
tess.pensize(3)             # change the pen width

tess.forward(50)
tess.left(120)
tess.forward(50)

wn.mainloop()