This is an illustration I've done over a couple of months (February - May 2014). It took about 20h of drawing and lining in total (though, to be fair, I've only worked on it about 1h-1h30m at a time over those months). 
As far as concept goes, I guess you could say I'm not the most cheerful of people. :)
I used B pencils and .005,.02,.04 black liners. I wonder how this worked if I'd have used ink. Hmm. Maybe in the next one.
This now belongs to a friend of mine (and wasn't meant for sale at any point). I do plan have a limited series of 20 copies screen printed, based on the Illustrator trace, once I find an amazing quality print shop in Amsterdam (tips are welcome).
Initial sketch
And the final image:
And here's the AI trace (with some fixed symmetries)
Thanks for taking the time to look at it all :)