d. Using a Trig. When a string line is stretched across a long wall, use a trig to prevent it from
sagging. A trig is a short piece of line that loops around the string line at its midpoint and fastens the
top edge of a previously laid brick in the middle lead. A piece of broken brick rests on top of the trig to
hold it in place (Figure 3-26).
Figure 3-26. Constructing a trig