GAIA

The GAI Computer Corporation developed their Earth Simulator “GAIA” to track things such as fluctuation in weather patterns and activity of the Earth’s crust, ultimately it was a tool designed to predict the future of the Earth itself.

The digitized Earth within this simulator is said to be completely accurate down to the smallest detail. However, as our story begins, progress on the simulator has been put on hold due to the events of the Sad Morning.

People were introduced to GAIA using the Arecibo Message, and then the people in the GAIA simulation built their own GAIA simulation, inside of GAIA, and then the same thing happened inside that simulation, and so on. This led people in the world of Anonymous;Code to worry that maybe their reality was just a simulation, too.

The GAIA simulation, after having humans introduced using the Arecibo Message, appears to be what is responsible for the existence of multiple world layers, simulations that exist inside other simulations.