What is the rule of polyhedra?

Could you please explain the rule of polyhedra to me? I understand that polyhedra are geometric solids with multiple flat faces, but I'm not familiar with the specific rule that governs them. Is it related to the number of faces, edges, or vertices they have? Or is there a more complex mathematical principle involved? I'm eager to learn more about this concept and how it applies to the study of geometry and cryptocurrency.