Maybe procedure by procedure. But they tend to interlock and inform each other, and that’s where the so-called emergence takes place.

Probably my single favorite bit of emergent play in rpgs ever is in Burning Wheel. The interplay of Let it Ride, explicit intent and consequences, Roll or Say Yes and the entire reward cycle come together in a way that I’m skeptical was by design. Each procedure was individually designed to address dysfunctional play problems, but they come together to create an entirely new play structure.

This doesn’t discount the genius of the design or the designers! But I think there’s a difference between those games, and games where the designer hides a cutesy psychological or mathematical or ethical trick inside their game.

Edit: this was in reply to Tim Koppang​. Y’all ran away with the thread there! (Please continue!)