A thought that came to you entirely independent of anyone else's thoughts... something that no one before you has thought or imagined, so that it includes absolutely nothing that's already familiar to you.
Now you're breaking off into something else that fascinates me... symbolism as a highly efficient method of communication. If you test yourself, you'll find it takes less time for your brain to process symbols than spoken words... and there's a very short amount of time in there where your brain understands what it's looking at without the need of any other language other than symbolism.