A quadtree does the same thing for two-dimensional space. It takes a rectangular region and divides it into four equal quadrants: northwest, northeast, southwest, southeast. If a quadrant has too many points in it, it subdivides again and again. Each subdivision creates smaller and smaller cells where points are densely packed.
Beagle Bros catalogs and manuals were filled with old-timey woodcut illustrations repurposed to tell jokes:
。关于这个话题，Line官方版本下载提供了深入分析
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+sleep_max: float