The most common levels used in retracement analysis, which are 61.8 percent, 38 percent, and 50 percent. When a move starts to reverse the three price levels are calculated (and drawn using horizontal lines) using a movement’s low to high. These retracement levels are then interpreted as likely levels where countermoves will stop. Fibonacci ratios were also known to Greek and Egyptian mathematicians. The ratio was known as the Golden Mean and was applied in music and architecture.