1. What 3D objects are represented by a pair of concentric circles in its plan (viewed from above) and a pair of concentric circles for its front elevation (vertical face)?

2. What would a #1 object be if it also has a side elevation that is concentric squares [with corner diagonals]?

(In reply to part 1 solution; thoughts on part 2 by Charlie)

I see a problem with your solution to part 1.  Consider the horizontal hole in plan view (or the vertical hole in front elevation view).  The outer circle in the drawing would have arcs cut off and replaced with straight lines (chords of the outer circle) where that hole meets the sphere.  (Easy to visualize if you picture a very large diameter hole with respect to the sphere's diameter.) 

Also, the drawing should show dotted lines where that hole goes through the sphere, shouldn't it?

I haven't even thought about part 2.  :-)

Posted by Ken Haley on 2006-08-03 00:38:13