This was a set of bases I did for CMON that was supposed to have a sewer look. The idea was that they would be modular, with some interchangeable pieces.
The supplies used were pretty basic. Sculpey, plastic deck plating, polystyrene tubing, and green stuff.
These images show how the flat pieces on top of a few of the bases could be changed out...
They wanted a bases that looked like a sewer grate, so I mad this one with individual walls and two different top pieces...
Here's a few more "traditional" marble designs that I made for them...