Cartesian Coordinates. XYZ axes. Cartesian coordinates can describe a point along a line, in a plane, or in a space. A central red point (origin) appears, X, and Y axes are shown (positive zones are brass coloured, negative are dark red). The positions +10 and -10 are indicated along the number lines. A point (purple) is in position 7 along the X axis, 5 on the Y axis, and 8 on the Z axis. These coordinates are written as (7,5,8). Shadows of the purple point are cast on each of the three perpendicular planes. The three coordinates (x,y,z) can specify a point anywhere in three dimensional space. All sorts of useful mathematical operations can be done using these coordinates