  Inspired by the universality of computation, we advocate for a principle of
spacetime complexity, where gravity arises as a consequence of spacetime
optimizing the computational cost of its own quantum dynamics. This principle
is explicitly realized in the context of the Anti-de Sitter/Conformal Field
Theory correspondence, where complexity is naturally understood in terms of
state preparation via Euclidean path integrals, and Einstein's equations emerge
from the laws of quantum complexity. We visualize spacetime complexity using
Lorentzian threads which, conceptually, represent the operations needed to
prepare a quantum state in a tensor network discretizing spacetime. Thus,
spacetime itself evolves via optimized computation.
