In 2014 you can see a 5 Elliot waves (EW) to the bottom. Each of the drop was smoother. Using Williams %R (W%R) momentum indicator, we could see that each of th1 1-3-5 point in the EW, the bearish ones, are related with W%R -80 levels, very oversold.
The Williams %R is a popular indicator because of its ability to signal a market reversal.
The difference between 1-2-3 points and W%R is the temporal length that remains in this area: very short in 1 case, longer in 2, and much much longer in 3. In this case (3) we can trace a V pattern (red line) over W%R with three sharp spikes in the center (1-2-3) that almost did not affect the price.
Curiously the bottom of that crash was reached AFTER this three spikes in the uptrend side of the V pattern, showing the ability if W%R poitting a market reversal. After wave 5, BTC follow a sideways movement and started to climb some months later.
Let's go with 2018 situation...