You need to anihilate all particles from the board.
How to play
Each time you click or tap on a particle, it clones itself. Positrons go right and top, electrons left and bottom. Two identical particles cannot coexist in the same cell, so if this would occur, the particle will not clone itself. And if two opposite particles meet, they cancel each other.
Each time a particle is cloned it counts as a move. You have to solve the puzzle with the minimal amount of moves. We still don't know that minimum!