I love Mystery caches. I especially love difficult Mystery caches! There is nothing like the "Aha!" moment when you spend hours, days, weeks, months or even years on a difficult puzzle, only to finally crack it wide open. I didn't always feel this way, in fact I found Mystery caches to be quite annoying when I first started. I eventually began to solve the ones I could, then I began to see how deep they could go...
Eventually I began to create my own puzzles, and for some time there was a really great puzzle exchange between several local cachers. We challenged each other with a lot of new ideas, and it was a blast! I was creating my "X Series" when finally life got in the way and I had to step back from caching a bit. Here's a bookmark list of my X puzzles that have been adopted by a cacher local to them since I moved away. These puzzles won't help you with this one, but perhaps you may want to check out some other difficult ones to warm your brain up if you get stuck on this one somewhere...
Can you get Homer to do his happy dance?
You can validate your puzzle solution with certitude.