Newtonian n-body · relativity-inspired visuals
Bodies move under Newtonian mutual gravity (softened, leapfrog-integrated). Nothing here solves Einstein's equations — the relativity is visual.
Curvature: the lattice is pulled toward each mass in proportion to its Schwarzschild radius rs = 2Gm/c²; the sheet is an embedding-diagram style well.
Time-dilation colours (the chosen relativistic effect): each body's clock rate is dτ/dt = √(1+2Φ/c²) · √(1−v²/c²). Slow clocks are shifted toward red and dimmed; a body whose rs exceeds its radius renders as a black hole. The grid uses the same mapping.