Abstract: The present invention provides apparatus and a method for projecting an indication of alignment. The invention features forming a first output beam, and a second output beam that is substantially perpendicular to the first output beam. The first output beam indicates level, the second output beam indicates plumb, and the first and second output beams together indicate square. An error indicator indicates an error in the accuracy of the first and second output beams as indicators of level and plumb respectively. The error indicator can be deactivated, such that the first and second output beams together can be used at least to indicate square.

Abstract: A portable, battery powered, self-levelling alignment tool for simultaneously indicating level, plumb and square. A projection unit including a laser diode, a collimator, and an optical system is located in a projection unit which is pendulously suspended inside a housing. The optical system divides a collimated beam from the laser diode and the collimator into output beams having a generally perpendicular relationship with each other. The projection unit may be balanced such that at least one of the output beams is substantially level and other beams thus indicate plumb or square.