These were inspired by art teacher John Post. You can find his robots and lots more ideas here
We talked about using separate shapes for the parts and joints so the robot could move. (I brought in a jointed wooden figure to help get this idea across. I didn't have a robot to bring in...)
Each artist mixed their own medium gray for the robot shapes, and then the lighter and darker grays for highlights and shadows.
Then it was on to the background. Students chose a color and then mixed the tint.
We added details and a border with Sharpie.
I love it when I'm at my schools when classes walk by our artwork- the kids are always so interested in what we have on display, and the teachers are complimentary too. I can tell my Art Club artists how much their artwork is enjoyed, and they love that!