Michael, this is awesome, thank you very much!
Kindest,
Gunter

You have also the other solution to make like a real gem builder! ;)

Take a box so yet a solid and make some boolean diff! ;)

You will be sure to have a solid!

HI gunter
我想，使用网格曲面可能是最快的方法（GIF是完整过程的演示，如果我对命令的位置更熟悉，可以更快），当然这需要对网格的曲线的选择有一定的理解，将对象拆分成一个个封闭的平面，使用平面命令是最好理解方式。
I think using mesh surfaces （network）may be the fastest method (GIF is a complete demonstration of the process, and if I am more familiar with the position of commands, it can be faster), but of course, this requires a certain understanding of the selection of mesh curves. Splitting objects into closed planes, using the plane command is the best way to understand.

Thank you Pilou!

Thanks for your help Suiyan