Extensions occur when an impulse wave can be further subdivided into another set of five waves. Diagonal triangles assume a wedge shape pointing in the direction of the larger trend. Corrective Waves Corrective waves, labeled with letters, move against the larger trend and represent the jockeying for position of buyers and sellers. This results in interesting shapes on the charts as the market is pulled against the trend and seemingly against its will. Not only do corrective waves take on a myriad of patterns, they also have their own variations.
Zigzags are easily recognizable three waves structures against the larger trend.
Flats also come in three waves but are essentially sideways in nature. Triangles are the familiar coiling patterns seen in other analyses but the boundary lines can both be contracting, one contracting and one flat or even both expanding. Without getting too detailed, the entire pattern is an extended sideways move. Flats may reach an intermediate extreme beyond the impulse wave they are correcting. Triangles usually are the final correction and therefore appear alone as a wave 4 or as the final part of a complex correction.