Imagine the scene below squished into two dimensions. That is the world of Flatland. The manhole cover becomes a platform with the ability to swivel. Lines (or rectangles) can advance onto its surface and be rotated. If, as shown below, a rectangle is only partly on board, it can be broken apart. It’s a good thing that, like the flatworm, planaria, the rectangles are self healing.  One may find a variety of misshapen rectangles in the vicinity of a roundhouse.

Roundhouse in Flatland
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