• ✓The same engine as 3D Rotation, in flat pieces
• ✓The technique first: fix on one landmark and turn the whole piece with it
• ✓The wrong pieces are flipped, not turned — and the game teaches that difference
• ✓No clock, and the step-by-step turn is always one tap away
• ✓A letters-and-digits level (b/d/p/q) for a child who muddles left and rightplanned

✓ = done · ☐ = planned. Every game is built one step at a time like this.