They could all be optimized a little by setting the step over and depth of cut better. These were all simulated with a 1/4" ball end mill, which could also be optimized with some end mill changes. It shows though that you can do a lot with tool paths and simple 2D vectors.
You can actually do a lot of “3D ish” stuff in VCarve without adding an actual 3D model or STL file, like these knife scales I did awhile back (I only ever cut the flat profiles, never got around to doing the full cut).