Understanding Forum Symbols and Icons

Can anyone point me to a guide explaining the various symbols that appear beside each forum topic? I’m referring specifically to those circles containing either a central flame or radiating lines. What do the varying circle colors indicate? Also, what does the red star on the circle represent? How does a black flame differ from a red one, and what is the meaning of the yellow flame? Is there a legend somewhere that lists all these different meanings? Thank you.

(Copied from another thread) These are "Topic Icons." I was certain there used to be a key for them, but it seems missing now. @Schnoff probably misplaced it during one of his many upgrades. The lines in the ring indicate test mode, meaning it is a simple text post. It will transform into a flame once it becomes popular. A grey flame signifies a "hot" topic with at least 25 reply comments. The small star shows that you have posted a response to that topic. Red icons denote unread or new topics. Some feature an "i", indicating the moderators have marked them as informational posts. Naturally, the lock designates posts that the mods have pinned to always appear at the top of the forum section. Also, a small bar graph beneath the topic text indicates there is a poll attached. Did I cover everything?