Harmonic patterns
Harmonic patterns (Gartley, bat, butterfly, crab) are XABCD structures whose legs follow precise Fibonacci ratios.
A harmonic pattern connects five points, X, A, B, C and D. Each type is defined by ratios: in a Gartley, for example, point B retraces about 61.8% of XA and point D about 78.6% of XA. The D zone is the potential reversal zone.
Their appeal is precision: entry, stop and targets are defined in advance. Automatic tools detect them on most platforms.
Their limitation: the ratios allow some tolerance, and many patterns fail. Wait for a price reaction in the D zone, a rejection candle for example, rather than entering at the exact point.