擅长:python、mysql、java
<p>有点像</p>
<pre><code>old_position = turtle.position() # Assume we're good here.
turtle.move_somehow() # Turtle computes its new position.
turtle_x, turtle_y = turtle.position() # Maybe we're off the canvas now.
if not (min_x <= turtle_x <= max_x) or not (min_y <= turtle_y <= max_y):
turtle.goto(*old_position) # Back to safely.
turtle.setheading(180 - turtle.heading()) # Reflect.
</code></pre>