The 3 used have default lengthes 72, 305 and 1292, calculated after the first length default value of 72. For each of the 3 only an upper line, set by default at 78.6%, is plotted in green and its complement, set to 21.4%, is plotted in red. When the closing price is above 3 green lines, we say it is Forbidden to Sell ( PV ), and when the closing price is below 3 red lines, we say it is Forbidden to Buy ( PC ). Those conditions are flagged on the chart. These PV-PC conditions were, up to my knowledge, first proposed by Bo Williams.
This update also include the indication of upward the EMA Fans formation. Those fans are formed when 6 Phi^3/2 distant EMAs are ordered, for instance, we say there is EMA Fan 610 if close > EMA 17 > EMA 34 > EMA 72 > EMA 144 > EMA 305 > EMA 610. As far as I know, this concept of EMA Fan was first proposed by Bo Williams.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.