Within suits, there are regional or national variations called "standard patterns." Because these patterns are in the public domain, this allows multiple card manufacturers to recreate them. Pattern differences are most easily found in the face cards but the number of cards per deck, the use of numeric indices, or even minor shape and arrangement differences of the pips can be used to distinguish them. Some patterns have been around for hundreds of years. Jokers are not part of any pattern as they are a relatively recent invention and lack any standardized appearance so each publisher usually puts its own trademarked illustration into their decks. The wide variation of jokers has turned them into collectible items. Any card that bore the stamp duty like the ace of spades in England, the ace of clubs in France or the ace of coins in Italy are also collectible as that is where the manufacturer's logo is usually placed.