wave1d example, propagating ca wave on different geometries.
n1 number of segments in section
n2 means each segment has n2 subsegments

wave1d_<n1>_<n2>.py -- n1 segments stick geometry
wave1d_taper_<n1>_<n2>.py -- n1 segments tapered stick geometry
wave1d_tree_<n1>_<n2>.py -- Y shaped tree, each section is n1 segs.
wave1d_tree2_<n1>_<n2>.py -- Y shaped tree + a branch sticking out of the middle of the trunk, each section is n1 segs.



