Elliott called sideways combinations of corrective patterns “double threes” and “triple threes.” While a single three is any zigzag or flat, a triangle is an allowable final component of such combinations and in this context is called a “three.” A double or triple three, then, is a combination of simpler types of corrections, including the various types of zigzags, flats and triangles. Their occurrence appears to be the flat correction’s way of extending sideways action. As with double and triple zigzags, each simple corrective pattern is labeled W, Y and Z. The reactionary waves, labeled X, can take the shape of any corrective pattern but are most commonly zigzags. Figures 1 and 2 show two examples of double threes. (Triple threes are quite rare.)

Key Takeaway: Impulses extend; corrections combine.

For a complete description, please read Elliott Wave Principle: Key to Market Behavior by Robert Prechter and A.J. Frost.