Race in a random landscape with three cars that are controlled with the accelerometer. Change cars by double tapping on the screen. Change of view is done by a hard double shake. It is possible to change between a set of default ground plates, sky domes, as well as controlling the fog color used as either default gray, fixed color, clock colors, or random clock colors. You can read the help and do color mode settings in:Applications->Rock Terrain 3DYou can buy the unlock key in the Wallpaper settings, it is the normal Google checkout flow presenting the small sum that sponsors coke and chips.(Note this app support inapp purcahse for a license key! The trial version of the wallpaper is free and displays a transparent locker, limits the swap between cars to 20 seconds before jumping back after 1 hour, and also only allows gray fog.)