I brought my greyscale markers with me to Worlds so I could practice toning. Next time I will make sure to get a wider selection, as I had 3 black, 1 10% warm, 1 20% warm, 2 50% warm, 1 80% cool and 1 20% cool grey marker. You can tone with that, but you can't really get a very wide range out of them...

Still, this was the first actual drawing I was able to get pounded out, and I think it turned out okay.