In Mabula, each of the two players start with 12 marbles in their color on the perimeter of the playing area. Placement of the marbles is randomized as long as no color has more than two marbles in a row, even around a corner.
On a turn, a player chooses a marble on the perimeter of the board, then moves it as many spaces as they wish across the board. If other marbles lie in this line, push them ahead of this marble, with the only restriction being that you can't push a marble so far that other marbles are pushed into the perimeter of play. Keep taking turns until no player can go. Whoever has the largest orthogonally connected group of marbles wins.
Alternatively, you can decide before starting that a player's score will be the product of the sizes of all of their groups. In this situation, the maximum score is 81 (3x3x3x3).