The technique is even older than that -- most graphics modes on the 8-bit Ataris only supported a 4-color palette. To get more colors on the screen, you had to

The technique is even older than that -- most graphics modes on the 8-bit Ataris only supported a 4-color palette. To get more colors on the screen, you had to take an interrupt partway through the frame to swap out some of the colors and then put them back during the vertical blank to be ready for the next frame.