Reach the exit. Swipe or use the D-pad. Tap the board (or press space) to stand still for one turn — timing is everything.
After a few moves your Echo appears where you started and replays your exact moves, a few turns behind you.
Doors stay open only while their button is held. You can't hold a button and walk through — but your past self can hold it for you.
The violet glow shows where your Echo will walk next. Stuck? HINT reveals your next 3 moves. One puzzle a day, same for everyone — solve it in par moves for a perfect.