Iteration Simplifies our Turtle Program¶

To draw a square we’d like to do the same thing four times — move the turtle, and turn. We previously used 8 lines to have alex draw the four sides of a square. This does exactly the same, but using just three lines:

for i in [0,1,2,3]:
    alex.forward(50)
    alex.left(90)

Some observations:

We’ve found a “repeating pattern” of statements, and reorganized our program to repeat the pattern.

import turtle             # Allows us to use turtles
alex = turtle.Turtle()    # Create a turtle, assign to alex
# Make alex draw a square
for i in [0,1,2,3]:
    alex.forward(50)
    alex.left(90)

(turtlesrevised)