Perpetual Testing Initiative

Storyline/Plot
The Perpetual Testing Initiative is a project administrated by Cave Johnson as the company was becoming bankrupt. Johnson promoted that the Multiverse Theory exists and that there are infinite universes with infinite Aperture Science facilities. The layout of the project is to trick the more financially-stable versions of Aperture, by planting blueprints of testchambers on the desks of unaware associates of alternate universes and stealing the chambers while they are constructed. Johnson admits that the project was indeed a con plan, and that they are robbing the more-stable versions of themselves to produce more testchambers.

Affecting Gamplay
The Perpetual Testing Initiative is a story-based plot on the second DLC of Portal 2. Players are allowed to use a new in-game map editor that is shown as a blueprint of a testchamber. The testchamber is then compiled through the Source engine and then rendered as an actual map. Players can then upload their creations by using the Steam Workshop, where other players can download and play testchambers freely. This map editor is only available to both PC and Mac versions of Portal 2.