cartesian coordinates topics covered in this cartesian coordinate systems the -axis and -axis the commutative property of addition absolute values and the abs(function this doesn' introduce new game instead it goes over some simple mathematical concepts you will use in the rest of this book in games the graphics on the screen can move left or right and up or down these two directions make up two-dimensionalor dspace games with objects moving around two-dimensional computer screen need way to translate place on the screen into integers the program can deal with this is where the cartesian coordinate system comes in the coordinates are numbers for specific point on the screen these numbers can be stored as integers in your program' variables grids and cartesian coordinates figure - sample chessboard with black knight at and white knight at