Hello all, I just saw this very nice tutorial by Paketa12:
youtube.com/watch?v=DI9ScmbJ6BY
Where he explains how to create linearly geometries, and thought I would port it to GLSL for the community, in case someone (like me) finds nodes sometimes harder to follow than code 
Find attached the .tox
Best,
Darien
Interpolation_glslVersion.tox (3.9 KB)