Is that popping out at me??

Contour line design with shading.  Sharpie and colored pencils on paper.  The curved or contour lines help to create the illusion that the objects are popping out toward the viewer.  To further enhance the illusion of popping out the students shaded each section by coloring hard in the corners and lightly in the middle.  This tricks the eye into thinking that the objects are being lit by a light source from above.