When diagonal triangles occur in the wave 5 or C position, they take the 3-3-3-3-3 shape that Elliott described. However, it has recently come to light that a variation on this pattern occasionally appears in the wave 1 position of impulses and in the wave A position of zigzags. The characteristic overlapping of waves 1 and 4 and the convergence of boundary lines into a wedge shape remain as in the ending diagonal triangle. However, the subdivisions are different, tracing out a 5-3-5-3-5 pattern. The structure of this formation (see Figure 1-20) fits the spirit of the Wave Principle in that the five-wave subdivisions in the direction of the larger trend communicate a "continuation" message as opposed to the "termination" implication of the three-wave subdivisions in the ending diagonal. Analysts must be aware of this pattern to avoid mistaking it for a far more common development, a series of first and second waves. The main key to recognizing this pattern is the decided slowing of price change in the fifth subwave relative to the third. By contrast, in developing first and second waves, short term speed typically increases, and breadth (i.e., the number of stocks or subindexes participating) often expands.
Figure 1-21 shows a real life example of a leading diagonal triangle. This pattern was not originally discovered by R.N. Elliott but has appeared enough times and over a long enough period that we are convinced of its validity.