Well. I will find simething about it.
Because I have no idea now.

WhatFor,

Download this indicator. It should be some comments inside the mql4 code in russian language. If you understand some of comments please let me know.

All that I understand that it is support and resistence lines based on Fibonacci numbers 23.6%; 38.2%; 50%; 61.8% and in some cases 76.4%.
The theory says that the the price is stopping on those numbers, floating between two lines sometimes etc. If the price left 3 lines this price will change the direction of the trend. Most probably. Those numbers 23.6%; 38.2%; 50% and 61.8% are the levels of market correction.