Here is the puzzle I recently made.
It also requires a little ball. You insert a ball into the left hole, and turn the puzzle around to make it go out of the right hole. It is not that easy – check out the map!
You are welcome to copy my design and made a similar puzzle yourself. Here is the drilling diagram. (1), (2) and (3) means drillling depth. Squares indicate entrance and exit. All the other holes shall be closed. (I had to introduce some abberations into the picture so you can see both left and right sides at the same time. The real puzzle does not look like that – see the first picture.)
I’m pretty sure you can make it look nice than mine. I usually only have enough patience for proof-of-concept.