Simple Stochastic Divergence.
Bullish - Price hits new low, Stoch at higher low (under 20).
Bearish - Price hits new high, Stoch hits lower high (above 80).
Bullish divergence displays green background with lime cross.
Bearish divergence displays pink background with red cross.
Options:
Adjust Stoch Length
Adjust Lookback period for lowest lows and highest highs