About this 3D model

Four slightly different types of dice, made for teachers. Each one is 20mm^3. The dents are made using about 45-degree cones for easy printing. This is also a simple starting project for someone to learn about 3D design-- cube, sphere, cones, alignment, cut, and intersections. Have fun! I initially made these dice without considering the traditional sum-of-seven configuration (6 and 1 are on opposite sides). I am not mathematically convinced that the numbers have to be arranged that way for fairness beyond the balance of numbers. Theoretically, the one (1) hole should be much bigger to balance the holes on the opposite side. Physically, I think we might need to balance the center of mass. Anyway, I added a traditional set. Thanks for the feedback and support.