This is a great assignment to focus on movement. Students have to combine cars or motorcycles in motion in a dynamic composition. Students choose the medium. My example uses marker. There are many examples online to show to classes.

Requirements:

1) Draw a car or motorcycle in motion or racing. You can draw more than one car or motorcycle

2) Needs to include a background that also shows motion. Background needs to be filled in. 

3) Needs to show a full range of value from light to dark

4) Shows good contrast

5) Needs to look like a full composition, not a sketch

6) You may choose the medium: graphite pencil, colored pencil, watercolor, marker, or sharpie

It is important to have one sketchbook assignment practicing shading of a shiny car. I also tell students no over smudging. We work so hard drawing the object as three-dimensional and then over smudging can cause it to look flat or two-dimensional.