The real author:
Egor
This indicator identifies the maximums (the minimums) of the market using volatility corridor of prices for a certain period of time.
The indicator will be useful when searching for the optimal market entry points during a trend reversal, and also when constructing trading systems for predicting trend changes.
A signal to the trend reversal is more exact where the volatility corridor is narrowed.
This indicator was first implemented in MQL4 and published in Code Base at mql4.com on 12.01.2010.  Â
Fig.1 The Extremum indicator.