quartet - Google Play

Wave the phone around to make pleasant music with as many as 4 instruments. Tap the screen to stop/start the music. Touch the top left corner to show / hide the settings. Press the Instruments button to display a list of instruments: Piano, Pan Flute, Strings, Tin Drums. Select one to listen to all the individual keys of that instrument. Use the Configure button to map the accelerations in the x, y and z directions to one or none of these instruments. The software self-calibrates, but if a new person is using the app, you may want to press Recalibrate

The buttons 1 to 5 let you set a beat pattern -- you have to tap out the pattern twice after you press the Clear Beat button, and the new pattern is automatically stored and played on the tin drums. The beat can be speeded up by sliding a finger horizontally from left to right.

On the screen is a small white ball that moves in the direction you tilt the phone. Circles of color that depend upon the orientation and movement of the phone appear on the screen at the location of the ball. The radius changes depending upon which direction of the compass you point the phone.

Everyone can use this to relax. However,a dancer could use this to make her own music while dancing, as could someone doing Tai Chi. A person who is tone deaf or blind can use this to easily make pleasant music as well.