(a–d) Snapshots at, respectively, = {π, π/2, 3π/2, 0}. Each image was taken at = 53° and t = 9000 M with . The axes mark the image's vertical and horizontal extent in the image plane in units of M. Far right: logarithmic color map used to make the images. The intensity is normalized to the maximum intensity of the composite image shown in Figure 2.