Lines plotted for the Low and High of the region of price that was Overbought or Oversold
(Low of the candle that became overbought and highest high in the Overbought period) (High of the candle that became oversold and highest high in the Oversold period)
I like to use the dotted lines as pivot points for the reversal of the trend, and also pay attention to small tops and bottoms (normal lines) that form in strong trends, as they usually make for brief periods of acummulation/distribution before the continuation of the strong trend.