“…The scroll wave rotate about a linelike filaments called vortex filament, and usually can be defined in terms of a phase singularity. In three-dimensional excitable media, the vortex filament is commonly a closed ring, and these vortex filaments can form linked and knotted rings which contract to compact, particle-like bundles [10,11,12,13,14,15,16,17,18,19,20,21].…”