Gravilux (Android) app for $0.99

Gravilux lets you touch a universe of simulated stars beneath your fingertips, exerting a gravitation-like force to twist them into an infinite variety of colorful new galactic forms. Just launch the app and start moving your finger across the screen. The stars will react, moving in slow waves and forming amazing shapes and fascinating effects. As these pinpoints of light float across the screen of your smartphone or Kindle Fire, you'll be overcome with sense of peace and serenity.+