These are auxiliary indicators that can help you analyse the situation on the market. They are based on a sequence of numbers, that were devised by the Italian mathematician Leonardo Fibonacci. It is widely used in technical analysis to calculate the levels of support (see) and resistance (see) in the market. There are Fibonacci lines in your terminal (see). On the top panel of your terminal there is a button with dotted lines and the icon F - this icon is for "Fibonacci lines." With their help, you can implement levels that show how the trend may change (see) or to what level prices rebound may occur (see). That is, there is a trend called the "corridor of the price chart." We can not even describe it as two straight lines, but we understand that the price could go at any time through the top, or also the lower boundary of the trend. Therefore, it's better to use a few lines with the help of the button mentioned above. With Fibonacci retracement, you need to identify 23.6%, 32.8%, 50% and 61.8% of the range of the current trend and establish new lines at these levels above the upper boundary and under the lower. As a rule, it can be quite difficult for newcomers to work with these lines, however you soon learn to understand this valuable information about price behaviour. To learm more about this trade system, you can read the book “The New Fibonacci Trader” by Robert Fisher.