Overview of the nine striations hosting bright grains marked in Figure 1. Each striation is represented by a continuum- intensity image and a TDD. The latter was extracted along the dashed line indicated in the continuum image. The faint dotted line in the TDDs indicates the time of the adjacent context image, and the diagonal dash-dotted green lines track the observed grains in time along the slit. An animated version of this Figure is available as an online movie.