Several video games based on the Magic: The Gathering franchise exist for multiple systems. Some have attempted to translate the card game to electronic play nearly exactly; others have taken more liberties and drawn more from the setting than the actual rules of the card game. Benefits of successful video game versions of the card game include convenience, practice, and challenge. However, artificial intelligence for a game such as Magic is an extremely hard problem, and such software usually must be continuously updated to stay current with recently released card sets. Video game versions often expand on artwork, and may include unique cards that rely on randomly generated numbers or variables, effects which would be difficult or annoying to duplicate in real life.