To be frank -- Quandary is so hard for me. I think I've got it and then suddenly I don't. I figured out the secret though...start strong and when you find yourself completely perplexed and you've run out of workable moves, simply stop. Pretend that was as far as you had planned to take it anyway and smile. Yeah, that's it...I had planned for all that lovely white space. That's my story and I'm sticking with it.
In addition to Quandary, I used Paradox (Zentangle(r) ) and Rims by DiAnne Ferrer. I love the way it all fit in String 129 (find it at tanglepatterns.com)