Trust me, I could have worded that unkindly if I was intending to be unkind. I understand that he is learning and what I am saying is that he is being taught Rhino very badly.
If your son wants to learn Rhino he would be well advised to consider my advice to do this without using the solid modeling tools. He will learn not just how to model this but also why what he is doing now is failing. And that will put him ahead of most of the people reading this.
That is not the intent. The intent is to get him to try doing this without the solid modeling tools. If he is willing to do that, he can ask all the questions he wants and I will be happy to help him complete this today.
I agree 100%. By teaching the solid modeling tools to new users who have no grasp of how to use Rhino without them they are just learning how to fail.