Reciprocal is a game where you must reproduce the pattern on the left side of the screen using the similar panel located on the right side.
Initially you can click a non-empty square (in the right side of the screen) in order to indicate the desire to subtract one piece from that indicated place. Clicking on another square the second time will finalize the move and add the piece to the newly indicated position, allowing you to repeat the process from the beginning.
You must respect the time limit for each game level. Higher game levels are usually more difficult compared to the initial ones. Good luck!