The multiverse is not a single theory but a collection of hypotheses suggesting our universe is one of many. Level I (infinite universe): our Big Bang region is just one patch; sufficiently far away, every possible history plays out. Level II (eternal inflation): bubble universes nucleate in an eternally inflating false vacuum, each with potentially different physical constants. Level III (many-worlds): quantum mechanical branching creates parallel histories at every measurement event. Level IV (mathematical multiverse): every consistent mathematical structure exists physically. The simulation explores Level II dynamics — bubble universes colliding and merging in a higher-dimensional space.

The grid you see is spacetime itself — each line is a coordinate in the higher-dimensional 'bulk' that contains all bubble universes. Each universe warps the grid around it proportional to its mass (Einstein field equations: Gμν = 8πTμν). Heavier universes create deeper wells; wormholes add a spiraling rotational component to the distortion. This directly visualises the stress-energy tensor's effect on spacetime geometry — the mathematical backbone of General Relativity applied to a multiversal topology.

When two bubble universes collide, they do not simply annihilate — they merge. In the simulation, the larger universe absorbs 15% of the smaller one's mass (the rest converts to the energy of the collision — gravitational radiation and heat). This asymmetric mass transfer mirrors actual bubble collision models, where the collision wall carries energy that partially transfers to the absorbing universe. The merged universe inherits the momentum vector of both, and spawn protection prevents immediate re-collision, giving the new bubble time to settle.

Wormholes are topological shortcuts through spacetime — Einstein-Rosen bridges connecting two separate regions (or in this case, two separate bubble universes). In the simulation, wormholes are transient: they nucleate spontaneously, persist for 5-20 seconds, and collapse. Any universe that collides with a wormhole is teleported to the other wormhole endpoint — its hue shifts (representing a change in physical constants after traversal) and its velocity is partially damped by the transit. The three rotating ellipses of each wormhole visualise the throat's tidal geometry.