These grasshopper functions takes a list of points and outputs a list of corresponding points which are either Next or Previous in the initial sequence.  The function has two inputs, 1. the initial list of points, 2: a boolean which determines whether the point sequence should treat the points a an open ended sequence or a closed loop, creating "tangent" like relationships.  

ex. if your geometry is circular and you want the sequence to assume continuity, you would choose true, if it was a line and you simply want it to end you would choose false.

---

NextPoint.ghx (download)

PrevPoint.ghx (download)