Write a hidden surface program (or a visible surface
program).  Build a model with polyhedral (flat surface
objects). By querying the objects and the camera determine
if a face should be visible from the camera (or eye point).
Put a glyph on each face facing towards the the camera.
That is find out if the face is a "back face" (facing away
from the camera). If it is not not a back face, put a glyph
on its face. Make sure that all surfaces that could be
visible have a glyph. Note, not all such marked faces may
not be visible. Be sure to walk around the world to check
your work. You need to turn in a image showing both glyphed
and non-glyphed faces.  That is an image from a different
camera angle than was used to determine where the qlyphs
should be.
<P>
You do not need to use the vtk glyph routines, how ever you
can if you want. A good place for the glyph would be the
center of the face.  You can calculate the center by
averaging the points in the polygon. Assume all faces are
planer.