Here are a few robot sketches from my sketch book. Robots are interesting to draw because they can be whatever shapes you can imagine. I used a Faber-Castell artist pen to create most of the sketches. The pen has a brush-like tip that is good for creating a variety of line weights. Moreover, that pen can sure move smoothly and quickly across the surface of your paper. After scanning the sketches, I added some type in Photoshop.