They travel at the same speed so the second ball always trails the first one. The game uses compressed air to shoot the two balls out of a tube almost simultaneously. You might wonder about how they keep the balls from hitting each other in a physical game. Later, in November, 2016, I noticed it at an Internet casino using Felt software. I first saw the game at the 2013 Global Gaming Expo and later at the Tropicana in Las Vegas on February 18, 2014. Double Ball Roulette plays like regular roulette, except with two balls.