I do this with writing. Even if the problem has 3 points, I write down a list on the whiteboard. Even if the part of the system I'm concerned about has two components, I draw two boxes with a connecting line. Then I stare at the board. It's surprising how effective this can be.

Edit: I suspect Sherlock Holmes was the first fictional character to employ rubber-ducking (albeit with Watson as the duck). Greg House would be a more recent example (who uses his entire team).