Theory :

This idea I found on the net. It was originally made by someone using "RicardoSantos" user name on one other trading platform forum. I liked the idea and the indicator is ported as is (there is no further explanation by "RicardoSantos" either, hence no further information here either, but I think that it is self explanatory once when you attach it to the chart)

Usage :

You can use the color changes as signals

PS: one "big picture" example too