The rule of Alternation

The rule of Alternation There is a general tendency for the pattern of the two corrective swings in a completed 5-wave sequence to alternate between a simple (very often an ABC) correction and one of the more complicated or complex Elliott corrections.

This is a very helpful observation, because if Wave 2 unfolds as a simple ABC correction then probability will suggest that Wave 4 is more likely to unfold as a more complex correction. And vice-versa, if Wave 2 is complex, then you should anticipate that wave 4 is likely to unfold as a simple ABC pattern.