Anticlockwise motion of newly-emerged flux around the pre-existing positive (leading) sunspot in NOAA AR 11429. Tracked fragments of flux are labelled A–C. In each image, vectors are drawn either to connect the flux-weighted centroids of two orbiting fragments (panels a–d) or to best-fit the major axis of merged fragments (panels e and f). In the bottom two panels, red circles highlight the position of a fragment (C) whose ≈180° orbit from the south of the sunspot to the north between panels was not successfully tracked using the vector method. This figure is available as an online movie.