Behind the scenes of slot machines are numerous patents that prevent competitors from using (profiting on) each other's ideas.

Things like the wheel, for example.

The largest slot machine manufacturer, International Game Technology, has long held a patent on using a wheel in a gaming device. It's most familiar in the Wheel of Fortune slot machine, where players get to spin a wheel for a credit award whenever a symbol lands in their game.

Bally Technologies has been in a heated court battle against IGT, trying to invalidate some of their patents. Namely the wheel, which Bally was successful in dismissing. (Bally had a vested interest, because they use a wheel of their own in their games, though to get around the patent, instead of the wheel itself spinning, the ball or arrow spun.) As a result, expect to see more slot machines with wheels in the future.

IGT struck back with a series of patents that Bally was infringing on, involving networked gaming and bonusing. This time the federal court ruled in favor of IGT, upholding the patents.

For years casinos have been talking about networking slot machines. Now you know why it's taking so long -- the technology is being held up in court.