The Harmonic Bat pattern has the following characteristics which can be used to identify the Bat pattern.
AB leg can retrace between 38.2% – 50% of XA leg
BC leg can retrace between 38.2% – 88.6% of AB leg
CD leg can retrace up to 88.6% of XA leg
CD leg can also be an extension of between 1.618% – 2.618% of AB leg