龟图 模拟乌龟在程序控制下在房间里行走 乌龟拿着一支笔只有两种状态 上或者下 当笔在下的状态时乌龟随着自己的移动画出图形 而向上时 不画-Map turtle turtle in the control simulation under the turtle walking in the room with a pen, only two states, or under the pen when the next state with the turtle to draw their own graphics and upward mobility are not painted