This type is used to specify the point and the piece that should be placed at that point. These two types are game specific. Go Othello Chess Gomoku, Renju Nine Men's Morris Backgammon Chinese chess Shogi Lines of Action Hex Amazons Gess Octi 3.5.1. Compressing is done by specifying rectangles instead of listing every single point in the rectangle. Rectangles are specified by using the upper left and lower right corner of the rectangle.
Rectangles are illegal - they've to be listed as single point.
However the points have to be unique, i.e. overlap and duplication are forbidden. To get an idea have a look at an example .