World items are items possessed by the game world, not a player. They can be used to define the state of the game world and have it respond to players. This makes ARIS far more capable as a multiplayer engine.
This post is an intro to world items: how they might be useful, how to use them, and the ARISjs you need along the way to get the most out of them. We will do this by looking at the design of a concrete example, The Button, an experimental game Jim Mathews put together for the recent ARIS Global Game Jam.