This Marionette network uses a custom node, which implemented the pixel-based try and error code (I think there is no other way to create voronoi, is it?) from here https://en.wikipedia.org/wiki/Rosetta_Code
Instead of Pixels it uses rectangles which were extruded in random height (ground height is different in every voronoi cell). And different full spectrum random colours (which would look much better with adapted colour design).
Carefull playing around with values. Do not enter to h