Your goal: Open the lock by setting the pointers in motion. The lock opens only if every pointer is pointing straight up, back where it started, when the movement stops.

Set up your lock. Each dial has tick marks around its edge. To change how many ticks a dial has, tap the number next to “ticks” and type a new one (up to 12). Use the + button to add a dial (up to four), and the × button to remove the last one.

Choose how many moves. Type a number in the “Move ___ times” box. On each move, every pointer jumps ahead one tick.

Watch it go. Press Go. Choose Slow to watch each move carefully, or Fast to finish sooner. You can switch speeds while the pointers are moving. Press Pause to stop, then Resume to continue.

Watch and listen. When a pointer returns to the top, its marker flashes and you hear its own note. The number under each dial tells you how many laps that pointer has made.

Did it open? When the movement stops, the lock opens only if every pointer is pointing straight up. If not, the lock stays shut. Try a different number of moves.

Start over. Press the reset button (↺) to set the counter back to 0 and return all the pointers to the top.