Mason's cord
A Maurer string (also guide ) is a taut string , identified by masons , is used to individual bricks or stones as well as to vertically horizontally aligned to wall up, thus in a "perfectly straight" line.
horizontal
First the corner tiles are neatly placed. Then the mason's cord is stretched at the top of the corner stones. Usually the cord is wrapped around a loose stone at both ends, and each of these stones is then placed on the corner stones that were carefully placed at first. The cord then runs between the top outer edge of the corner stones.
vertical
The vertical is determined by tying a weight to the lower end of a mason's cord. The bricks in between can then be set up both in alignment and in height along the stretched, non-sagging cord.
Wall corners
Often the master bricked the four corners of a floor to full floor height. These four corners then provide the journeymen with the guidelines for attaching the mason's cord and lining the individual layers of stone.