next up previous contents
Next: period 6 Up: Cycles for a Previous: Period 126

Period 12, 12 phases

Figure: : Evolution from a gap 4 pair; no phase is shifted nor reflected relative to any other.  

Some cycles run their course without returning to the same symmetry class; others may shift the original configuration several times before returning to their original form. Alternatively, they may pass through a reflected image before repeating; most cycles of the form operate by reflection but a shift by half the length of the ring could produce the same result. Sometimes there is no distinction between translation and reflection. If N and p are relatively prime, quite long periods can result.

Amongst the last two examples, all the phases of Figure gif are distinct, wheres Figure gif manifests reflective symmetry. Given the way that boundaries interact, a pair with one gap may evolve into a pair with another gap, and then evolve back into the original pair, although this phenomenon is not present on a ring of length sixteen.

Harold V. McIntosh