I tried this with some ordinary spackle I picked up at the hardware store and it worked out well; I glued a plastic bottle cap over the hole in the center of the CD to give some height to the peak of the island center and then just built up the spackle around it, shaping it with a knife and then filing parts after it dried. I also tried a trick where I "picked" at the wet spackle with the tip of a screw which provided a sort of rippled effect like rapidly splashing water--I was thinking of using it as water "energy vortex" in my next game of Dystopian Wars.
