This is a useful shading exercise to practice scrubbing, crosshatching, and pointillism. Students create a basic scale of 6 values in the 'ladder', and then try to get a smooth transition between the values in the 'snake'. I have used this worksheet with 9s, 10s, and 11s, but would be good for other grades also. Prints out on a legal sized page.
Included is a photo sample of a completed worksheet for reference.