According to Weyl (1952), the word symmetry commonly has two different meanings. In one sense, symmetry is defined as a group of transformations that map an object into itself. This usage is reflected in expressions such as bilateral or rotational symmetry. In a broader sense, "symmetric means something like well-proportioned, well-balanced, and symmetry denotes that sort of concordance of several parts by which they integrate into a whole. Beauty is bound with symmetry" (Weyl, 1952). We will use the word symmetry in this broader sense.
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