Displacement field for the sample with (D,l)=(100, 40) under ε=7.5%. (A) Each grain has a flower-like pattern. (B)–(E) The zoom-in subareas are labeled in (A). (B), (C) The center of a flower is a fixed point with a topological charge of –1. (D) A flower is cut by a dislocation gliding (straight line, i.e., a domain wall), forming topological charges –1 and –1/2. (E) A flower is cut by two dislocation gliding, forming two –1 charges and two –1/2 charges with two domain walls.