如何维护步骤动画

Question

我正在尝试制作一个程序：

1. 模拟随机行走

2. 使用cs1graphics设置行走动画

   • 从黑色的中间块开始
   • 采取随机步骤，从来没有被踩过变成红色，重复步骤变成蓝色。你知道吗

import random
from cs1graphics import *
from time import sleep

def animationWalk(walk):
    print("Animation of Random Walk: ", end = "\n")
    window = Canvas(250, 250)
    window.setTitle('Random Walk in Manhattan')
    for y in range(10) :
        for x in range(10) :
            cue = Square()
            cue.setSize(50)
            cue.moveTo(x*25, y*25)
            window.add(cue)

    (x,y)= (6,6)
    squares = Square()
    squares.setSize(25)
    squares.moveTo((x*25)-14, (y*25)-13)
    squares.setFillColor('black')
    window.add(squares)
    been = Square()
    been.setSize(25)
    been.moveTo((x*25)-14, (y*25)-13)
    window.add(been)
    for direction in range (len(walk)):
            if walk[direction] == 'N':
                #y -= 1
                (x,y)=(x,y-1)
            elif walk[direction] == 'E':
                #x += 1
                (x,y)=(x+1,y)
            elif walk[direction] == 'S':
                #y += 1
                (x,y) =(x,y+1)
            elif walk[direction] == 'W':
                #x -= 1
                (x,y) = (x-1,y)
            been.setSize(25)
            been.moveTo((x*25)-14, (y*25)-13)
            been.setFillColor('red')
            cue.setSize(25)
            sleep(0.25)
            cue.moveTo((x*25)-14, (y*25)-13)
            cue.setFillColor('blue')   

def randomWalk(x,y):
    block = []
    for i in range (x):
        block.append([])
    for i in block:
        for j in range(y):
            i.append(0)
    position = (x//2, y//2)
    h = position[0]
    v = position[1]
    walk = ''  
    block[h][v] += 1
    while (h != -1) and (h != (x-1)) and (v != -1) and (v != (y-1)):
        directions = random.randrange(1,5)
        if directions == 1:
            v += 1
            walk = walk + 'E'
        elif directions == 2:
            h += 1
            walk = walk + 'S'
        elif directions == 3:
            v -= 1
            walk = walk + 'W'
        elif directions == 4:
            h -= 1
            walk = walk + 'N'
        block[h][v] += 1

    print("Starting at Center (", x//2, ",", y//2, ")")
    print("Walking Directions: ", walk)
    print("Track of Random Walk:", end = "\n")
    for entry in block:
        print(entry)
    animationWalk(walk)


def main():                     ## define main program
    x = 10
    y = 10

    randomWalk(x,y)
main()

一个正方形的颜色应该在参观时变为红色，再参观时变为蓝色，经过时变回红色。我不能让这些积木在被踩下后保持颜色。你知道吗