This is one of the images in my vision. I will provide another different image of "V" reversal pattern later, it will be same as 12/24/2018 reversal, SPY will go to new high.
In this image, SPY is in the Elliott waves wave #4, and in a smaller Elliott waves wave#3 (w3).
285-290 is the target of wave4.
If there is Gap to wave4 trend line, Wave5 target will be T1=235, T2=220;
Verify the midway Gap will help to measure the whole trend range.
I personally used Gaps:
G1: Trendline break Gap. Gap up/down to break the previous Trend Line.
Start a new trend in opposite direction.
G2: Midway Gap. This shows 40-50% of a trend;
Next range will be the other 50-60%.
G3: Exhaustion Gap. It is after a big trending range.
This shows near the end of a trend;