Value subtleties are often lost for people who are visually impaired. The higher the contrast, the easier it is to discern shapes. I thought it would be good to teach about contrast in art by having students limit themselves to white paper and black or a dark color. I had them draw or trace shapes that overlapped. X's were drawn on every other shape to give the composition a checkerboard affect. This process only works as long as 3 lines don't intersect (as in the letter "Y"). It has to be an even number of lines coming together at intersections. Then the students were asked to paint or color the shapes with the X's.
Students with almost no vision, used Wikisticks to trace stencils. The student who made the piece to the right, chose water color as his medium.