This could be any effect that transitions from one bitmap to another, or even one 3d scene to another. Some examples would be fading the screen, a horizontal or vertical wipe, or a page curl.

It was judged on the following criteria, in order of importance:

1. Originality/Quality of Effect.
2. Performance. Should run smoothly on a 3 Ghz machine.
3. Modular design. The goal was for a function or set of functions that encompass the entire effect, which could be easily added to a project.