Create more duplicates and decorate them along the border of the rectangle. Select and merge all the star layers.

多复制一些小星星放置在矩形周围，并将这些小行星合并为一个图层。

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The given maze doesn't contain border (like the red rectangle in the example pictures), but you should assume the border of the maze are all walls.

给定的迷宫不包含边界，但迷宫四周都是墙壁。

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