Bottom panel: trapped (white) and escaping (green) rays emitted by a spherical point flash from the ISCO of a Kerr BH with dimensionless spin a/M = 0.99, as mapped onto a small sphere co-orbiting with the point source (Equation (5)). Black dot denotes the direction of the center of the hole, with rays to the right being emitted against the orbital motion. Red lines show the boundary between trapped and escaping rays for a sequence of BH spins, a/M = 0, 0.5, 0.7, 0.9, 0.95, 0.99. Top panel: fraction of the escaping rays appearing in delayed pulses (hexagonal dots), and fraction of all rays escaping to infinity (square dots).