Margo

Margo is an abstract board game similar to Go, except that it's played with marbles which may stack upwards. A special capture rule means that captured pieces that support enemy pieces are not removed.

Margo is played by two players, White and Black, on a square grid which is initially empty (6x6 is the standard size).

Each player has an unlimited number of balls of their color.

Players take turns placing a ball of their colour either:

At an empty board point, or

Stacked on top of four existing balls (of any colour).