```
from turtle import Turtle, Screen
screen = Screen()
screen.bgcolor("lightgreen")
turtle1 = Turtle(shape='turtle')
turtle1.color('red')
turtle1.speed("slow") # = 3
turtle1.penup()
turtle2 = Turtle(shape='arrow')
turtle2.color('blue')
turtle2.speed(4) # "slow" (3) < 4 < "normal" (6)
turtle2.penup()
# user input function
perimeter = screen.numinput("Track Perimeter", "Please enter the perimeter:", default=2000, minval=500, maxval=3000)
def full_track_crawl(turtle, shortside, longside):
speed = turtle.speed()
turtle.pendown()
for j in range (2):
for i in range(0, int(shortside), speed):
turtle.forward(speed)
yield(0)
turtle.left(90)
for i in range(0, int(longside), speed):
turtle.forward(speed)
yield(0)
turtle.left(90)
turtle.penup()
# set the track
def drawTrack(perimeter, ratio):
shortside = (perimeter / 2.0) / (ratio + 1)
longside = ratio * shortside
screen.setup(shortside * 2 + 60, longside + 40)
turtle1.setposition(-shortside - 10, -longside / 2)
turtle2.setposition(10, -longside / 2)
generator1 = full_track_crawl(turtle1, shortside, longside)
generator2 = full_track_crawl(turtle2, shortside, longside)
while (next(generator1, 1) + next(generator2, 1) < 2):
pass
drawTrack(perimeter, 2)
screen.exitonclick()
```

Result:

Ref.