Angle bisector

This object was a very useful one. It was called an Egyptian plumb line, and was used to determine of a surface was level or not. Plumb lines were used in the construction of the pyramids, and can still be used today. A plumb line  is an angle bisector when a surface is completely level, because the string hangs right in the middle of the angle formed by the stands. I myself built a version of this kind of level, where a string hangs down with a weight on it. This picture was found at the URL http://www.touregypt.net/featurestories/tomb.htm, through google images.