How is the parallax effect working without using my mouse and shaking my laptop? Am I going crazy or do Mac Books Pro have accelerometers? Edit: Had to google

How is the parallax effect working without using my mouse and shaking my laptop? Am I going crazy or do Mac Books Pro have accelerometers? Edit: Had to google it, they have something called Sudden Motion Sensor http://support.apple.com/kb/HT1935 http://support.apple.com/kb/HT1935