4th/5th Grade Secret Cities-- Drawing in 3-d, shading

Secret Cities
The 4/5s learned  how to draw 3-d forms and include shading and shadows.  They stacked these shapes to make a "secret city".  

I got this idea from a book about drawing by Mark Kistler. 

This artist had a series of television shows that taught kids how to draw 3-d pictures step-by-step.  Here is a video of a "secret city" mural.