Hey everyone! Not posting this as an official suggestion because it's only $3 retail (and you should buy it).
I've been playing a game called Strata, and I think it's really great. It's casual puzzling boiled down to its purest form. No distractions, and no fluff. It's vaguely reminiscent of early 2000's puzzle games like Descartes Enigma, and that is certainly a good thing.
Strata is a beautiful game. The minimalistic graphics and interface are gorgeous, and a joy to use. The musical sound effects are pleasant and relaxing, and everything about the game just oozes class.
I urge you to try out the demo and support Strata on Steam Greenlight