AA: In one repair shop, there was a real cheap, sleazy color bar generator [for testing televisions]. And instead of doing color properly by synthesizing the p

AA: In one repair shop, there was a real cheap, sleazy color bar generator [for testing televisions]. And instead of doing color properly by synthesizing the phases and stuff like that, it simply used a crystal that was 3.58 megahertz [the carrier frequency for the color signal] minus 15.750 kilohertz, which was the horizontal scan frequency. So it slipped one phase, 360 degrees, every scan line. You put that signal on the screen and you’ve got a color bar from left to right. It really was really the cheapest, sleaziest way of doing it! AA: Anyway, part of the way into the design, Nolan said, “Oh, by the way, it has to be colored.” But I knew he was going to pull this stunt, so I’d already chosen the crystal [that drove the chip] to be 3.58 MHz, minus 15.750 kilohertz. SC: So, in the home version of Pong, the graphics would simply change color from one side of the screen to the other? AA: Right, the whole goal for doing this was just to put on the box: “Color!” I'd never seen Pong in color, but having a simple color gradient across the screen works very well for the game. You can see the ball changing color as it crosses the screen, which is a bit weird, but nothing else looks out of place: https://www.youtube.com/watch?v=F73cgR63Jn4 https://www.youtube.com/watch?v=F73cgR63Jn4