G-band and Ca ii H filtergrams of active region NOAA 10960 taken at 15:51 UT on 6 June 2007 a), c). The red and blue contours mark the position of orphan and regular penumbrae, respectively, and are based on smoothed G-band intensity images. The arrows show the apparent horizontal motions of structures in the G-band b) and Ca ii H d) filtergrams. The thick lines below the beginning of the x-axes correspond to 1 km s^-1. The yellow dashed contours in a) and c) mark the boundary between the inward and outward apparent motions seen in b) and d), respectively.