Triangles precede final moves - and that is seen clearly in the chart of the Canada TSX index . 2017 saw a multi month triangle formation and then a breakout rally to new highs that ended Abruptly. Why wave 4 end up being triangles, the right answer is that this is just Mass human behaviour as reflected in the EW fractal and that is how it is. The behaviour is the same in the same situation. The fall from the top of wave 5 is now a five wave decline marked as A and we are in B.