Simulated CD showing relative brightness of echoes, where gray‐scale indicates relative brightness, with darker gray corresponding to brighter echoes. To distinguish faint points, they have been circumscribed with darker gray circles; the reader is reminded that the shade of gray inside these circles indicates brightness. (a) Full CD, viewed face‐on. (b) Random points illuminated by the echo parabolae from all epochs. (c) Panel (b) inclined along the CD axis of symmetry.