This is presently beyond my knowledge. Which best practice techniques should I use to draw this little puzzle? It's symmetrical, the main tube diameter is round and approx.. 4". Towards the end the round tube is flattened a bit and has a larger circumference of about .75". The ends of the torus are opened and are rounded off. The object has a shelled interior. The last detail has a cut away along the interior portion of the model. I have been stumped for some time trying to imagine how to draw this. Any input is appreciated.