I'm doing a fractal in Bryce now, well sort of a fractal. The cheating kind ;-)

Place a mirrored plane vertically in the middle of your scene, and turn it until it's just a straight line in the middle (see purple line in image).

Add a few objects on, say, the right side of the mirror. They will be reflected on the other side. It's very easy and fun. Not sure if this is what you're looking for.

Doug