Op Art 1 Recreate the study shown here to the left in your sketchbook to recreate a sphere in 3D (op art). Complete dark and light with your pencil. (Be sure to add the last step of shading!) 2. Create a 7″ square (trace square) in the center of a page in your sketchbook. Draw three different size circles in the square. Draw the lines as shown and follow the demonstration shown to the left. Use complimentary color to complete in colored pencil. 2.