I blame this one on Saveen Reddy's video...
Expressive Diagrams with Visio 2007 (2009-03-22) (http://vimeo.com/3813486)
Are we firing at Will? Star Trek, Next Generation.
By the way, Saveen's little video is very good. Little long, but good. He makes a comment about using shadows to get a third (actually, a fourth) color, and observes that the shadow can be made larger or smaller than the primary shape, but, he's not found a need to use smaller. That raised my curiousity. So, attached are two shapes, that I tried to make as identical as I could. One with a larger shadow, and one with a smaller shadow. The differences are subtle. I guess if you're not into the artsie side of Visio, you won't much care.
For the curious...