Fess per Fess

Fess per fess crenellé az and gu. 

A division of the fess horizontally through the middle by a straight line. The fess may be thus divided by any of the various lines used in heraldry, which must be particularly mentioned, such as engrailed, indented, embattled, etc.
Note.—The Fess may be divided throughout all the various lines of heraldry, per pale, quarterly, per saltire, per chevron, barry,  bendy, etc.