First appearing in 1991 as a demo included with Silicon Graphics computers it resurfaced ten years later as a commercial game.

tranquility defies genre classification -- it is an arrhythmic music game in which the player (an abstract viewpoint) floats in a sea of starlit geometric structures in order to pass through targets called spinners - it is a bit like hide-and-seek. Play is self-paced and self-directed; there are several commands to control game speed and difficulty, including an auto-pilot button.

As much a game as a state of mind.