Grids, boxes and a stylus.
The concept of the game is simple enough. You have a grid of black or white squares. Your goal is to change all of the squares black, white, or solid horizontal lines of black or white. Where is the challenge? Well, you have to perform this task without lifting the stylus. When you move the pen over a block, it will switch its color. You can mover from left to right or up and down, no diagonals. There are 100 puzzles that you can solve using these basic instructions. The first ten are easy; they go up exponetionally from there.
If you get tired of trying to solve puzzles, there is the challenge option. This has a Tetris feel to it. Blocks falls down and you have to get all of them either black or white. When you do, they disappear. Blocks continue to fall and if you do not eliminate them fast enough, you lose. The plus to this option is that you can get rid of the blocks in steps instead doing to the pen-left aspect of the puzzles.
There is a head-to-head option to the game that only requires one cartridge; it requires you to turn the DS on its side to view the action. This took a little getting used to because it is not the usual way you hold the DS.
Finally, there is an option to create your own puzzles within the game to challenge your friends. You cannot create an unanswerable puzzle because part of the creation process is to provide the answer to the puzzle.
This is by no means a great game. It is a decent game that I paid seven dollars on clearance at Target. I would have been very disappointed with the title if I paid thirty for it, but at seven dollars, it was worth the small investment.