Color Blocks are multi-colored diamonds which appear in large groups. In its most pristine state, a Color Block is colored blue. Touching it once turns it green, a second touch will turn it yellow, a third touch turns it red, and a fourth touch makes it disappear. Their main purpose is to block the pathways players need to use.
Sonic the Hedgehog (16-bit)
Color Blocks first appeared in the original 16-bit version of Sonic the Hedgehog, where they are obstacles surrounding one of the six Chaos Emeralds in the Special Stages. Here, the player has to drill through them to get Chaos Emerald. The Color Block groups in this game are even larger in two Special Stages which are based on wild arenas instead of mazes.
Sonic the Hedgehog 4: Episode I
Color Blocks make another appearance in the Special Stages of Sonic the Hedgehog 4: Episode I, where they have a similar role. In this game, the Color Blocks start shrinking every time they are hit until they finally disappears completely.