I added to the challenge unintentionally by choosing to practice on a block with narrow quilting spaces. The swirls are supposed to be circles, but many of mine had a bit of a tail, which made them look more like sea shells than tight swirls. That's not necessarily a bad thing, just not the result I was expecting.
All that said, swirls make a really cool design and overall, I'm very happy with my first attempt.
I've already incorporated the swirls into a "real" project, which I'll be ready to share later this week. Next up on the quilting practice schedule: leaves.