Anthropomorphic polygon

That is, for exactly three polygon vertices, the line segment connecting the two neighbors of the vertex does not cross the polygon.

For two of these vertices (the ears) the line segment connecting the neighbors forms a diagonal of the polygon, contained within the polygon.

For the third vertex (the mouth) the line segment connecting the neighbors lies outside the polygon, forming the entrance to a concavity of the polygon.

[1] It is possible to recognize anthropomorphic polygons in linear time.

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