Evolution of the loop intensities in different AIA channels. Panel a.1 shows the time-averaged 211 Å image. The boxes of different colors highlight the locations from which the average intensities (DN s⁻¹) shown in panel a.2 are derived. The same, but for the 193 Å and 171 Å channels, is shown in panels b.1, b.2 and c.1, c.2, respectively. The vertical line in each panel of the bottom row indicates the time stamp at which the loop is first seen to move downward in the 171 Å channel.