Tap the well to set a stone · press & hold to drain sand · drag the dial (or enable Tilt) to move where down is.

Gravwell is a simulated pocket sand table. Thousands of grains in six mineral strata fall toward whichever direction gravity points. Use the gravity dial to steer, tap the well to place a stone obstacle, press and hold to drain sand away, then fossilize the composition and save it as a PNG.