This top-down 2D simulator drives a binary neutron star inspiral with the real Peters-equation gravitational-wave decay rate: heavier, closer stars lose orbital energy faster and spiral in quicker. Adjust each star's mass and the initial separation, then watch the orbit tighten and the gravitational-wave chirp climb in frequency and amplitude as merger approaches. At contact, the simulation compares the combined mass to the Tolman–Oppenheimer–Volkoff limit to decide the remnant's fate live — a surviving (possibly hypermassive) neutron star below the limit, or a prompt collapse to a black hole above it — and either outcome triggers a kilonova flash whose ejecta color-codes r-process nucleosynthesis of heavy elements.