Or, in other words, the stuff of heraldry!
If you're painting knights you can't get around it. To make my life easier when designing heraldry for my knights, I made a little colouring-book style sheet to work out how designs for heraldry would work. Not only on the shield, but also on the horse's caparison or in the livery of a knight's retinue. I didn't want to discover halfway through painting that a certain combo or design didn't work out after all. I'd rather waste 10 minutes and some paper, than spend hours on a miniature and having to strip it...
I mentioned this sheet on the LAF and offered to scan it.
So I thought I might as well put it up here.
Here is the design sheet I use:
This is the one that I used in deciding on a colour scheme for my recently painted knight and retinue:
If you need a primer on how to design heraldry, this one seems pretty complete and thorough: www.internationalheraldry.com