Relating this back to video games, there’s a reason why ( on your old C64 and Spectrum tapes ) there was no nice looking, patterned border to frame your game outside of the play area ( something that was completely possible, and helped with the aesthetics of the game ): someone patented it.
Also, when you were racing around a track, you used to get a ghost driver ( Hard Drivin, and many other games had this )… then, Sega started enforcing it’s patent.
I think the problem with a lot of patents like this is that companies get patents for obvious gameplay related techniques ( obvious in that most game developers implementing a racing game, would probably come up with the ghost driver concept ). This restricts other companies, coming up with the idea themselves in order to further the gameplay of their titles, then can’t use it without hiring a lawyer to ensure that small print has been read, and purchasing ( probably from a limited budget ) a number of patents for their new “original” game.
Does anyone have a link to a list of game related patents? It would be cool to come up with a game that used them all ;)