Parallel lines are lines that never cross each other - they keep the same distance apart from each other. When two lines intersect, the opposite (X) angles are equal. On parallel lines, alternate (Z) ...
This is meant to be a cheap way to program W27C512 EEPROMs which require 14V erasure voltage and 12V programming voltage... Or basically any other 24/28/32 pin ROM requiring from 5V to 27V programming ...