add animation examples

Come up with examples where you can create animations.

Once there is a `wait` fn, an animation in Logo can created by drawing a picture, calling `wait`, calling `clean`, and doing it over again with another picture.

An animation using Logo functions will need to handle looping, termination, and loop state that each loop's picture can use. The easiest way is probably `(dotimes [i MAX-FRAMES] ...)`

首先检查现有的 Logo 函数，以及使用 wait 和 clean 的拟议动画流程。按照建议使用 dotimes 和 MAX-FRAMES，定义涵盖循环、终止和循环状态的示例。完成的标准是：repository 包含可用的动画示例，并演示这些行为。

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