"Mani" is the Tantric Buddhist mantra OM MANI PADME HUM in Tibetan script. The mantra means "Hail to the Jewel in the Lotus," which is compassion: the wish for all beings to be free of suffering and its causes.

This mantra is that of the Bodhisattva of Compassion Avalokiteshvara, or Chenresig in Tibetan. His Holiness the Dalai Lama is seen as an emanation or manifestation of Chenresig.

The mantra floats in the center of your monitor and revolves, as if around a cylinder, much as do actual prayer wheels in many areas of Asia, where the teachings of the Buddha flourish.

Attractive all by itself, and can be used as a screen saver as well

More info on Prayer Wheels : http://www.inner-tranquility.com/tibetan-prayer-wheels