Awww gee whiz, thanks for the kind words guys!
I didn't use a pattern... Just whatever was floatin' around the old noggin. The blue one took about an hour. The red and black ones took a few hours each--I had to wait for the sharpie paint to dry after each layer.
Here's a picture of what the skulls look like pre-makeover. I plan on using the picture beside it for some sort of alter maybe... I'm not entirely sure yet. I'm open to suggestions!