See drawing done at sketchcast.com.
See vectorized version at VectorMagic.
These 10 drawings were done specifically for the Illustration Friday topic of "hats". All of them were drawn in sketchcast.com, followed by post-processing with various graphic software. To watch the sketchcasts, please follow these links - drawing 1, drawing 2, drawing 3, drawing 4, drawing 5, drawing 6, drawing 7, drawing 8, drawing 9, and drawing 10.