11. Initially Langdon s ambigrams followed the yin / yang model, featuring rotational symmetry . 12. They have instead a discrete rotational symmetry , often fivefold, like a regular pentagon. 13. A typical cryptic crossword grid is generally 15?5, with half-turn rotational symmetry . 14. Eudicots with tetramerous or pentamerous petals may have rotational symmetry of order 4 or 5. 15. Thus, for example, wallpaper and crystals cannot have 8-fold rotational symmetry . 16. The resulting figure has rotational symmetry only. 17. The event-symmetry can then be extended to a larger N dimensional rotational symmetry . 18. In this case, there is spontaneous symmetry breaking of the rotational symmetry of the Hamiltonian. 19. Rotational symmetry is symmetry with respect to some or all rotations in-dimensional Euclidean space.20. Monocots are identifiable by their trimerous petals, thus monocots often have rotational symmetry of order 3.
