Flats are always a 3 wave structure. Structure = 3-3-5 Wave A is a three wave pattern and never a Triangle. Wave B is subdivided into a three wave pattern. Wave B retraces to at least 105% of Wave A & typically up to the 138.2%. Wave C does not go beyond Wave A and is "Truncated". Wave C always subdivide into 5 wave structures: a Diagonal or an Impulse wave.
Guidelines:
Waves A and C connected usually is parallel to the Line connecting the origin of the ZigZag to point B. Waves A and C usually are Equal in length.