Two Question on Differencing

[Cygnus]

Generally speaking, the next "generation" would probably difference by dividing the bordure per fess, and the generation following that one would divide per cross (quarterly). In all probability variations in the lines of partition would also be tossed in for the chevron, as well as for the bordure.

I'm very surprised by how many variations one can get, especially with such a simple "undifferenced" shield.

That said, Sandy's suggestion of a bordure compony counter-compony is probably the technically better choice, especially if the Herald failed to use all of the options available to him when composing the differencing of the coat of arms. In that same vein I think a bordure billettee argent and azure would probably be a better choice, although it may look like the dreaded compony at first glance. Bastard!

I also think the difference between billettey and compony is more immediately obvious than the difference between chequey and compony counter compony. So, for those who may be following along (and who are visual learners like I am), here's the same chart with the "mystery" shield filled in.
(I assumed it would still be a bordure divided per pale even though MacMillan of Rathdown didn't say so in his description, so please tell me if it's incorrect and I can modify it.)