What does PAO stand for, and what is the system?

Person–Action–Object: every item you memorise gets a fixed person, a fixed action, and a fixed object — so you can fuse several items into one scene.

* Each card owns a full Person/Action/Object — the composite takes the Person of card 1, Action of card 2, Object of card 3, and drops the rest. *

You assign each of your items (each playing card, or each number 00–99) a permanent three-part identity. Once every item has its own Person, Action and Object, you can build a composite image by mixing slots from different items — the Person of one, the Action of another, the Object of a third — packing three items into a single picture. That fusion is the whole point of PAO.

Go deeper:

• PAO within the peg-system family (Wikipedia) — places PAO among the classic peg systems.