Python龟碰撞

我该如何碰撞？因此，乌龟/蛇不会开箱即用。试图使它们停留在（-200，-200）和（200，200）内。

from turtle import *
from random import *

def bounding_box():
    up()
    right(90)
    forward(200)
    down()
    left(90)
    forward(200)
    left(90)
    forward(400)
    left(90)
    forward(400)
    left(90)
    forward(400)
    left(90)
    forward(200)
    up()
    goto(0,0)
    down()

def drawSnakeRec(segments, length):
    if segments <= 0 or length <= 0:
        return 0
    else:
        color(random(), random(), random())
        forward(length)
        pensize(randint(1,10))
        left(randint(-30, 30))
        return length + drawSnakeRec(segments - 1, randint(1,20))

def drawSnakeIter(segments, length):
    TL = 0
    while segments > 0:
        color(random(), random(), random())
        pensize(randint(1,10))
        forward(length)
        left(randint(-30, 30))
        TL += length
        segments -=1
    return TL


def main():
    segments = int(input("Enter the segments between 0 and 500: "))

    bounding_box()

    hideturtle()
    speed('fast')

    if segments < 0 or segments > 500:
        print("Segments is out of range. Segment must be between 0 and 500 inclusive")
        input("Press enter to close")
    else:

        x = drawSnakeRec(segments, randint(1, 20))
        print("Recursive Snake's Length is:",x,"Units")
        input("Press Enter to go on Iterative Snake")
        up()
        goto(0,0)
        reset()
        bounding_box()
        y = drawSnakeIter(segments, randint(1,20))
        print("Iterative Snake's Length is:",y," Units")
        input("Press Enter to exit...")
        bye()
main()

有什么帮助吗？谢谢。因此，我正在尝试完成此操作。是的，这是我要完成的实验室作业。如果你们可以帮助我或提供我可以做的事情，那将是很棒的。PS：我对乌龟不好。我以前从未学习过乌龟，但是我还是学过一点点Python。