Your goal in Cat-a-comb is to get your cats stacked in all the right places.
To set up, each player takes all six cat cubes of one color (black or white). Place the nine tiles — three each of brown, white, and black — into a 3x3 grid, then choose a player to play the three neutral brown cubes on a tile of each color. The other player then takes the first turn.
On a turn either place one of your cats from your reserve onto a neutral cat or opposing cat that is sitting directly on a tile, thereby creating a stack of two cats, or take a stack of cats from a tile and distribute them on the board, placing the bottommost cat onto an adjacent space, then the next cat onto a space adjacent to the one just placed, then (if present) the final cat adjacent to that one. (A stack can consist of one cat.)
You can never place two cats of the same color directly on top of one another, and your turn cannot end with a stack taller than three.
You win at the end of your turn if (1) you have a cat on the top of the stacks of all the tiles of one color or (2) you have a cat on top of three stacks that are each three cats high.