Fold Triangular grid

Hi there,

I am currently trying to fold a triangular grid in the same way a Chinese style hand fan by controlling the depth of the folds using distance from a curve. Currently, i can only get this to work if use a square grid and try and triangulate it later which gives me little control of the ordering.

I like the pattern that the triangle grid component gives and i get the surface to move in one direction as shown in the attached image but i can't split the data into two so that i can send every other row in the opposite direction to create the folding. I think the problem may be my limited knowledge of path mapping as i can split the data to do the inverse part of the operation but i can't piece it back together.

Can anybody help? thanks in advance!

Triangulation%20tessalation.gh