It's hard to pin down exactly what it is about Clapper's designs we like. Maybe it's just the fact we have a weird obsession with patterns, and she seems to tap into that obsession every time she makes anything. What's more interesting is the fact she does so in a new and interesting way each time.
For this one, she also did some silk screening, which, as we've seen time and time again, is the quickest and easiest way into our hearts. It's one thing to make a kick-ass flier, it's another to think it's kick-ass enough to spend a whole bunch of time doing an extra step to bring it to the people. That's besides the point here, because we'd have picked it even if it was photocopied on twenty pound copy paper.
The key thing about this flier -- and probably Clapper's work in general -- is that even though the patterns seem systematic and computerized, they're not. They're (seemingly) done entirely by hand, and that's noteworthy. It works perfectly for the bands, too, who all have folkish roots of one sort or another and can be encompassed with a fancy, almost old timey image.