A rhythm game series by Harmonix that doesn't depend on special peripherals. All that's needed is a PS2 controller. Each song has 6 main tracks (drums, guitar, etc.). On each track, there are a bunch of gems representing that track's instrument. Hitting all the gems on a track for two measures activates that track temporarily. Your job is to move around the tracks and hit all the gems to keep them all activated.The first game was Frequency, followed by a sequel, Amplitude, both on the PS2.Made by Harmonix, who went on to make Guitar Hero and Rock Band.
The game provides examples of: