So far, we've been drawing quads and cubes, but if we want to draw more complex geometry, it is probably handier to model it on a 3D modeling tool rather than doing it by code. We can cover multiple chapters on this topic, but let's just look at a quick example of how can it be done and you can extend it to your needs.
We have used a Blender to model our example data. Blender is a free and open source 3D modeling toolset and can be downloaded for free at its website: https://www.blender.org/.
For this example, we haven't modeled an extremely complex example; we've just used one of the primitives that Blender provides: Suzanne:
To simplify our importing tool, we'll select the object mesh under the Scene | Suzanne ...