This is an indicator that compares the rate of change as a proportion to the Feigenbaum Constant (The black line). The green line is a positive divergence from the rate of change, the red is a negative divergence from the rate of change. When the Red line is on top and the green line is on the bottom, then that is a bearish trend. When the Green is on top and the red is on bottom, that is a bullish trend. The black line also helps indicate a general bullish or bearish trend based on how it moves.
When the lines "open up" that means a trend is beginning, when the lines close that means the trend is ending. This indicator is a powerful leading indicator and needs sensitive eyes. Every small movement needs to be given consideration.