Thank you for the kind words! I hadn't thought of the witches of MacBeth but you're totally right. I see that now.
Yes, black outline and limited lighting made my life so much easier. The feel don't look good? Just erase them. Don't want to waste time on a background? How about solid black. As for the UI it's the same idea. So much easier to create a "button" by just writing the word "Rest" on the screen with a green 'R'.