Zentangle Challenge #153 - UMT - Jailed Johnny

This week's Zentangle Challenge from Laura at www.iamthedivaczt.blogspot.com is to "Use My Tangle" Jailed Johnny. I've done a couple of tiles using this one so far this week and have to say it sure looks different when used in a longer line with more "petals", or with duplicate rows. I had a bit of time this afternoon and decided to try the renaissance tiles again, and include the new Jailed Johnny. I love the renaissance tiles, but would love to take a class in just working with them - they are so different! I have a question - does anyone out there know the best sharpener or way to keep a white charcoal pencil sharpened? I have three different sharpeners, but the chalk lead keeps breaking off ...