We study the flow of signals through paths with the following condition: a node emits a signal if two incoming signals from other nodes arrive consecutively or if it receives an external stimuli. We apply our study to count and describe families of polychrony groups  and we introduce triangular sequences.
We study the flow of signals through paths with the following condition: a node emits a signal if two incoming signals from other nodes arrive coincidentally or if it receives an external stimuli. We apply our study to count and describe families of polychrony groups on a line, and we introduce triangular sequences.
R
consecutively
coincidentally
A
on a line,