The Green Quill - the simple icon that I had begun to use when I was working as a Scribe within the Midrealm of the SCA. Since scribes didn't sign the front of their work, the simple green quill was something that I could hide in the design somewhere on the surface. It became something of a hieroglyphic signature that I began using not just in my scribal work but also in other venues.
Second to the quill, though older in use, was that of an oak leaf -specifically a white oak leaf (quercus alba). Green, the color of nature, and the image of the oak tree were all images that had a deep-rooted connection for me. In the SCA I was known as 'Thomas the Green' which came from 'Thomas the Green Guy' or 'Thomas the guy wearing the Green Tabard".
So in creating a symbol that would accurately represent me I had to incorporate those three concepts into one design.
Then I tried a triangle of oak leaves. That really got my attention because the interior space started to look like some celtic twist-spiral thing; a triskelion. This was a cool, if unintended design feature but it didn't look quite right. I might still use the design element - but not sure in what.
So then I pulled an image of an envelope and added the symbols to see what the seals would look like in action.