Mesh are calculated from “Cross Points”. To create a mesh we need al least four lines( bottom, top, left,right) and must to cross between them to create four “Cross Points”.
This four “cross Points” generate a mesh. The lines can cross between them several times, and sometimes there are more than one “cross Point” between two lines.
The system automatically use the best “cross point”, but if you need, you can select which “Cross Point” is the best.