I think, after all these years, I've finally had a good idea for a blog. A purpose for which a blog would be perfectly suited; some sort of Analogy Library. I'm always coming across things which would be the perfect other half for an analogy; something that you're certain would come in handy as a metaphor for something but you're not sure what yet.
For instance, Ben told me at the weekend of something called the Shepard Tone. It's a combination of tones that sounds like it's continually descending without ever getting lower. The ear can't decide which tone is the fundamental and so occasionally slips to another one, thereby keeping the descent going. You can listen to an example here.
Doesn't that just strike you as something you could use metaphorically sometime? It's got to be a good analogy for something, just not sure what.
Incidentally, the Shepard Tone is not to be confused with The Deep Note, or The Brown Note. Both of which also offer metaphoric possibilities.