8.2. Using Repetition with Turtles¶

While learning how to draw with the turtle, we have found many reasons to repeat ourselves in ways that a loop can make easier. A simple example is a square procedure - it needs to do both forward and right 4 times. So why not have a for loop repeat those for us:

The following program should define a procedure triangle that uses a loop to help draw a triangle. The main part of the program calls that function twice to draw two different triangles.

Arrange and indent the blocks correctly. You will not need them all.

        def triangle(turtleName):
---
    for side in range(3):
---
        turtleName.forward(120)
        turtleName.right(90)
---
        nick.forward(120)
        nick.right(90)  #distractor
---
#Start of main part of program
from turtle import *
space = Screen()
---
nick = Turtle()
triangle("nick")
nick.right(180)
triangle("nick")

The following program uses a turtle to draw a 175x150 rectangle as shown below, but the lines are mixed up. We want to define a rectangle procedure that repeats twice the process to draw half of a rectangle: draw a line for the width, then turn, draw a line for the height, and turn again.

Arrange the blocks into the correct solution and indent them properly. You will not use all of the blocks.

        def rectangle(turtle, width, height):
---
    # repeat 2 times
    for i in range(2):
---
    # repeat 2 times
    for i in range(2) #paired

---
        turtle.forward(width)
        turtle.right(90)
---
        carlos.forward(width)
        carlos.right(90) #paired
---
        turtle.forward(height)
        turtle.right(90)
---
        turtle.forward(150)
        turtle.right(90) #paired
---
from turtle import *
---
space = Screen()
carlos = Turtle()
rectangle(carlos, 175, 150)