The Z-axis. Its function is far more important in life than most people would ever give it credit for. Anyone who knows how tall they are, and I assume that's all of us, will know all about the Y-axis. Got to take something off the top shelf for a person not quite as tall as you, that'll be the Y-axis. The X-axis is equally a part of all of our lives. It's 3 miles to the supermarket? That's the X-axis. Your room is 15' long? X-Axis again. Anyone who has ever done basic mathmatics and plotted stuff on graphs understands the X and Y axis.



Link: Overclock3D