Summary

Have you ever used the randomness function in OpenSCAD? If not, why not? Here's a nice little demo of rands() for you. The clam opens its shell to a random angle, and if you're lucky, there will be a chunky pearl inside!

I took the original clam .stl, and hollowed and split it, using Meshlab and Blender. Theoretically it is possible to do all of it from within OpenSCAD. However, hollowing a model in OpenSCAD is...unwise. You must subtract the original model from a large cube, take the minkowski sum of that with a sphere, and then intersect that with the original model. And minkowski() on an organic shape like this would take FOREVER. So I did it in Meshlab and Blender.