Theory:
This version can easily be tracked down. It was originally published in an TASC article “Double-Smoothed Stochastic” by William Blau and was published way back in 1990. The calculation is defined as:
where:
C = Current close
La = Lowest low in a days
Ha = Highest high in a days
Ey = y-day exponential moving average
Ez = z-day exponential moving average
This version:
It is calculating as described, and is adding signal/trigger line for easier trend assessment.
Usage:
You can use color changes as signals.