I stole this image from Ma Hoyt. I don't think she'll mind. I needed a prism example 'cause I've been pondering a sermon that I heard. The basic idea was that Jesus is the prism and that He makes us look beautiful like a rainbow. And I disagree. The trouble with that idea is that it logically follows that the light would have to be coming from us, and that's just not how it works. Christ is the light. We don't do anything but reflect His light, since everything good comes from Him, and without Him is darkness. So. Who could be a prism if you really wanted to keep the analogy? Well, I reckon that'd be us. We can make His light appear more beautiful to others, but we have to be turned the right way. If we are turned the wrong way, we just block His light.
I ran across another possibility, too. It puts Jesus as the prism, but it has the light coming from God the Father. In that illustration, Jesus makes the light of God visible to us. I like that one the most. It makes more sense. I guess someone should tell the preacher-man that his sermon was a bit too man-centered and not quite...right. But that's not gonna be me.