Signed distance fields
It would be fun, I thought, to be able to specify the desired cross-sections, and have something generate the required 3D shape (if it existed) in real-time.
Dealing with all of the details of creating a mesh with the right vertices etc. sounded painful though. Fortunately, I had been reading recently about a different kind of 3D rendering technique which makes these kind of boolean operations trivial – signed distance fields.