A tile swap game where the objective is to create closed circuits. Closed circuits score and are then replaced with new tiles sometimes causing a cascade effect.
You can play on a square grid (easier) or a hexagonal grid (much harder).
Totally free! No in-app purchases.
Pattern recognition games have been shown to be great for brain exercises.
Making a move that fails to form a circuit will cost you one Move. Bonus moves are awarded for especially long circuits. The game ends when you have no more moves.