Very good design ideas, quite suitable for the needs of patients with obsessive-compulsive disorder.
There is a small problem. The original intention of this design is to get a fairer distribution result without using precise measurement methods. If perfect results can be obtained step by step according to the diagram, have you ever considered that if you start to cut the knife without finding the center of the circle at the beginning, the final result may not be so satisfactory, what should you do?

pretty good, huh

It turns out that this is the perfect slice cake.

The mechanical feeling of the cover picture is a bit too heavy. I thought it was something like sheet metal. I can't see it as a cake knife