Building 3D objects

Build a world with a number of objects that you build using at least three of the following list.

You will need to do some work your self, but you can use most of the tools in vtk. For example you might write a simple CSG program, or use the CSG tools built into vtk. Vtk also has a contour filters that could be used for the blobby objects. If you do a blobby object, use any function for gradiations (including linear). No matter how you build the objects you need to include a description of the steps and tools used to build the items.