Fourth grade has been working on Op Art and spheres!
They love the Op Art visuals - I mainly focus on Bridget Riley and Victor Vasarley. I show some Escher too, but focus more on the idea of optical illusions and math concepts used. They love looking at the visuals - I could probably spend an entire class with just a slide show of Riley and Vasarely!
We then transition to value, and shading spheres properly. I turn off the lights and break out my flashlight and a ball to demonstrate how light hits a sphere. Shading and value take at least a full class (and some frustration) for the students to feel comfortable, but it is all worth it in the end! The fourth grade artists loved when they could take a tissue to their shading and really blend those values together. Here are a few finished works! 
