Broad-line region structures of NGC 5548 based on the dominant emitting regions of the broad optical/UV lines as a function of distance to the center and of height above the midplane. The emission regions of the individual lines that are observed at different epochs are connected by a solid line. The dot at radius zero gives the size of a Schwarzschild black hole (with M = 6.7 × 10⁷   M_⊙) multiplied by a factor of twenty.