This is one of my first mandala style drawing that attempts to describe structure and perspective. The design is based on a four-fold symmetry axis with perspective vanishing points in the center, and at the edges of the cross-like structure. Spheres is an 14″x17″ pen and ink drawing, drawn using a .25 mm Rapidograph pen and black India ink. The design was created using a pencil, compass, ruler and protractor.
Here is some close-up detail of parts of the drawing. You can see the intricate pen strokes that are incorporated into the drawing, all added to the drawing free-hand with pen and ink.