Here's a sketch I did this morning, done with my ole Tombow dual brush marker which I haven't used in a while. I'm not sure why. I actually think I forgot I had it. The marker has two tips on either side: one being a big felt-tip brush and the other a medium nylon-tip. Anyway, I always liked using the Tombow pen because the nylon-tipped side makes a crisp "crackling" line that cuts into the paper nice. The brush pen side is now losing ink (supposedly there's only 1 ink reservoir for both tips), but it still makes a nice faint gradient for shadows. In case you're wondering, this is a sketch from a Paris photograph mixed in with random objects on my coffee table.