The pattern incorporates the 0.886 XA retracement, as the defining element in the D area. The B point retracement must be less than a 0.618, preferably a 0.50 or 0.382 of the XA leg. The Bat utilizes a minimum 1.618 BC projection. In addition, the AB=CD pattern within the Bat is extended and usually requires a 1.27 AB=CD calculation