Symmetry Set: Geometry, Shape, Topological Skeleton, Bitangent

Fundamental Domain: domain, Geometry, Symmetry group, Symmetry, Topological space, Group (mathematics), action,...

Straight Skeleton: Polygon, Topological Skeleton, Simple Polygon

Cone (Geometry): Dimension, Shape, Plane (geometry), Locus (mathematics), Perimeter, Rotational symmetry, Area,...