Let's begin our treatment of continuation patterns with the tri­angle. There are three types of triangles—symmetrical, ascend­ing, and descending. (Some chartists include a fourth type of tri­angle known as an expanding triangle, or broadening formation. This is treated as a separate pattern later.) Each type of triangle has a slightly different shape and has different forecasting implications.
Figures 6.1a-c show examples of what each triangle looks like. The symmetrical triangle (see Figure 6.1a) shows two converging trendlines, the upper line descending and the lower line ascending. The vertical line at the left, measuring the height of the pattern, is called the base. The point of inter­section at the right, where the two lines meet, is called the apex. For obvious reasons, the symmetrical triangle is also called a coil.
The ascending triangle has a rising lower line with a flat or horizontal upper line (see Figure 6.1b). The descending tri­angle (Figure 6.1c), by contrast, has the upper line declining with a flat or horizontal bottom line. Let's see how each one is interpreted.