Usually, you can narrow it down to a small pool of potential matches, but in Parallels, you can request or offer fic, art, or vids, so that narrows it down even more--in my case, I only offered art because there wasn't anything that I really wanted to write at the moment, so I could exclude any possible requests that didn't include art.
Anyway, it's an interesting prompt that's going to require careful thought on my part, because it could go any of several ways and I'm going to have to invest time in deciding what's a good thing to do that will intersect between the sorts of things I want to try with my art right now and the sorts of things the requester would like. (Yeah, it's vague and describes what every single person participating in the exchange is going through. That's the trouble with secret exchanges. :)
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