it's a cool monocramatic. i think you should bring the black of the ying yang more into the black of the rectagle like you did with the right half though. not too much of a deviation.
It'd be cooler if the lines were straight. Not to dis your work or anything, but I like straight lines.
Curvy lines CAN be interesting. The reason it bothers me is because they are really almost straight, like they want to be straight but they're just not quite there. If you're gonna do curvy lines, then go all out and make them really curve is what I say. (for instance, on the yin yang, where the line is supposed to curve, it's a little too straight for my taste)