Optical Illusions — Includes background on the Op Movement. Student's worksheet has them identify what type of illusion it is and includes enlarged images for display or print. 3 pages of additional optical illusions and a page of the most famous op artists round out this presentation. Combine this with drawing practice with sets:
 
Optical Illusions #1 ! — 9 different optical illusions for students to try their hand at practicing, these are more beginner level with #2 being a little more advanced. Each on it's own worksheet with a step-by-step and then a practice area at the bottom. I have also included a template for a 3D cube and a Flextangle.
 
Optical Illusions #2! — 9 different optical illusions for students to try their hand at practicing. Each on it's own worksheet with a step-by-step and then a practice area at the bottom. 
 
I like to have students draw optical illusions on these and then assemble as a final project. Great in pencil, colored pencil and thin sharpies/markers. Can be used as a lesson alone or as intro/practice before the real and final project, bell ringers, sub plans, virtual learning, etc.