### 微重力方块类练习题

```"""
微重力方块.py
程序运行后,按上下左右键操作小方块,它好像在太空中一样。
一不小心就会在惯性的作用下一直滑动。读者可以把本程序改
造成一个小游戏哦。练习是完成move方法.
"""

from turtle import *

class Square(Turtle):
def __init__(self,keys,colour):
"""keys：按键列表，colour：颜色"""
Turtle.__init__(self,shape='square')
self.keys = keys   # 上下左右键
self.color(colour)
self.penup()
self.dx = 0
self.dy = 0
self.screen.onkeypress(self.moveup,keys[0])
self.screen.onkeypress(self.movedown,keys[1])
self.screen.onkeypress(self.moveleft,keys[2])
self.screen.onkeypress(self.moveright,keys[3])
self.move()

def move(self):
"""不断地移动"""
pass # 请结合上下文自行编写本段代码
# 会员可直接向博主索取源代码,其它文章省略的代码也一样.

def moveup(self):
self.dy = self.dy + 0.1

def movedown(self):
self.dy = self.dy - 0.1

def moveleft(self):
self.dx = self.dx - 0.1

def moveright(self):
self.dx = self.dx + 0.1

if __name__ =="__main__":

screen = Screen()
screen.delay(0)
screen.bgcolor("black")
screen.title("微重力方块")

keys = ['Up','Down','Left','Right']
square = Square(keys,'cyan')

screen.listen()
screen.mainloop()

```