Pick your cube's size from the pill at the top (2×2 up to 21×21).
Hold your cube the standard way: on odd sizes, the white center on top and the green center facing you. On even sizes, the yellow–blue–orange corner at the bottom-back-left with yellow facing down.
Tap Paint and copy each face onto the 3D cube; drag a finger to paint several stickers at once. Done fills in anything you skipped.
Tap Solve and follow the moves with ▶. The arrow and the tinted layer show what to turn.
drag stickerturn that layer (any layer)drag backgroundlook around (two fingers or right-drag work anywhere)U R F D L Bturn a face (Shift = counter-clockwise)←→spacestep through a solution3Rnotation: only the 3rd layer from the right
2×2: the true shortest solution (never more than 11 moves). 3×3: Kociemba's two-phase search always finds 20 moves or fewer ("God's number"), then spends a moment hunting for shorter; if the search runs to completion, the result is labeled optimal. 4×4 and up: centers first, then corners (and middle edges), then the edge pieces, using pure 3-piece swaps. Solutions are long but every step is shown.