Fig. 2. Basic topological structure of vortex from art to science.

The topological structures of a the Penrose Stair⁵⁵, b, c a Möbius strip⁵⁶, and d the phase of a vortex soliton (Hilbert factor) are isomorphic, i.e., a physical value (displacement or angle) continually increases along a closed loop and coincides exactly with the origin after a roundtrip. c From ref. ⁵⁶. Reprinted with permission from AAAS