This indictor is based on a 3 candle rule, which helps detect the trend change. It decides the the change of trend by comparing with the last 2 candles.
1) Bull case- High of the current candle is greater than the previous candle + the low of the current candle is greater than previous candle and close of current candle is greater than high of previous candle.
2) Bear Case- High of the previous candle is greater than the current candle + the low of the previous candle is greater than current candle and close of the previous candle is greater than high of the current candle. Denote this by a beginning of bear trend.
The bull or Bear symbol will appear 5 minutes before the market closes in timeframes >= 1 day however for lower timeframes, it will appear after the close of the candle.
Happy Investing/Trading :-)