Albert Einstein said, “You cannot beat a roulette table unless you steal money from it.” He might have been surprised. Roulette wheels have subtle flaws, and in this technological age a sophisticated observer can make some serious money:

• In 1873, British engineer Joseph Jaggers hired six clerks to study the wheels at the Beaux-Arts Casino in Monte Carlo. One wheel showed a clear bias, which Jaggers exploited to the tune of $325,000.
• As early as 1961, mathematician Claude Shannon had built a wearable computer to find likely numbers.
• By the late 1970s, a group of computer hackers known as the Eudaemons were frequenting casinos wearing computers in their shoes.
• In the early 1990s, Gonzalo Garcia-Pelayo used a computer to analyze the roulette wheels at the Casino de Madrid. He won more than $1 million over a period of several years.
• In 2004, a group in London was using a special laser cameraphone and microchip to predict a ball’s path, a technique called sector targeting. They won £1.3 million.

In both of the latter two cases, the casinos mounted legal challenges — and lost. If you’re not influencing the ball, the courts ruled, you’re not cheating. Modern casinos monitor their wheels to keep them as random as possible, but the long-term odds favor the engineers.