New Tripoli is a simulation nested inside a simulation inside a simulation. Click down through the layers — or use the breadcrumb — and watch how far you've drifted from physical reality.
◆ In-world canon · §15New Tripoli operates as a nested simulation stack — characters compare it to a Matryoshka doll or an Inception-style dream-within-a-dream. The four layers are canon (§15):
L0 Earth Prime — physical reality; the Human Server Stadium outside Tripoli, on Saharan solar. L1 New Tripoli — the primary persistent sim; the cavern, ring and downtown. L2 Residence interior — every front door is a holodeck threshold. L3 Sim Room — a dedicated room that is a full environment of its own.
A resident sitting in their bedroom's Sim Room is three layers deep. The ETI supplies tutorials, guides and classes for navigating the stack, and therapy programs for the small population that develops layer-disorientation psychosis. By New Ganymede, the Sim Room has become the home most residents actually live in — the main floor demoted to a social lobby.
See also: the Time Dilation Instrument (each layer can run at its own clock) and Canon - New Tripoli.md §15.