1. First, fold a round cake in half along its diameter.

2. Next, cut the folded round cake in a parallel direction at a certain distance from the folding line. At this time, it is cut into 3 pieces.

3. Then overlap 2 of the pieces and make the second cut to make 4 pieces.

4. Finally, overlap the 5 pieces and cut the third cut, which will make 10 pieces.