The base framework is there which used 3D points to create a 2D voronoi. However, I don’t understand how to “extrude” the form to get the 3D undulating walls of the pattern like in the image.
A simple way to do this is with a trim surface created in Rhino. I internalized an example for such a surface. Note the normal is pointing downwards which might seem wrong at first but the surface is used to create a boolean difference with its bounding box.
The inner voronoi group has some offset problems which I didn’t look at.