Time evolution of individual flare structures (footpoint ribbons) observed by SDO/AIA (panels a)−d)) and STEREO/SECCHI-EUVI (panels e)−h)). Observations are provided at channels 193 Å (panels a)−b)), 304 Å (panels c)−d)), 195 Å (panels e)−f)), and 304 Å (panels g)−h)). Panels in the left and right columns reflect the situation before (9:26−9:31 UT) and after (9:35−9:36 UT) formation of the new flare structure (arrow 3) that is visible between the older ones marked by arrows 1 and 2. Positions of individual loop footpoints (see middle panel in Fig. 9) are marked by crosses A−D in panels b) and f).