Hehe thank you! for classes i gotta check my docs, there are a few. But for prefixes the letter always defines the anomaly and the number stands for its number on the roster. They are from czech, so P is Item (Předmět), B is Being (Bytost), D is Dimension (Dimenze) and F is Phenomena (Fenomén). They let the employees quickly know what they are dealing with!
Sorry, it was a bit dark, I guess… In Iran a common strategy of combating falsifications involved leaving one's fingerprints on the ballot; it was done by dipping one's thumb in a bottle of ink, and that, as you may have figured out, leaves a characteristic blackish mark. So, the question is: what's happened to his fingers?