That's pretty exciting!  Thanks, Helle.  I knew of sea creatures who did this, but had no idea land snails did the same thing.  (And thanks to Geert for the link!)

I was so absorbed in your challenge I even talked to a coworker about it.  He will be fascinated to know the answer!

Thank you for such a fun challenge. 

"If your pictures aren't good enough, you're not close enough."  ...  Robert Capa