I made a square top bowl from a piece of katalox.
First I mounted the wood with a faceplate on the lathe and turned the outside in this way.
During the turning a large chip of wood broke off which I glued back and as a precaution I treated some cracks in the wood with glue, and then I finished the outside.
I then laser engraved my logo on the bottom and then glued a piece of leftover plywood on top with hot melt glue and turned it into a tenon.
I reverse mounted the bowl with the tenon in the chuck and turned the top in this way and hollowed out and finished the bowl.
After I finished the bowl I removed the plywood tenon with denatured alcohol and finished the bottom.
I finished the bowl first with two layers of sealer and sanded in between and finally with friction polish.
The bowl is 26 centimeters square and is 6 centimeters high