Relative profile of intensity variations seen in a transversely oscillating loop studied by Verwichte et al. (2010) using TRACE as a function of distance along the loop. The solid circle is the measurement of the intensity variation at the loop foot point. The long-dashed and dashed curves are functions –0.13sin(3π/L) and –0.13sin(5π/L), respectively, representing a possible third or fifth standing harmonic of the slow mode.