Examples of fitting to a damped cosine curve. The POS displacements are shown as black diamonds with error bars joined by a dotted line, while the blue line indicates the best fit to Eq. (2) using the mean parameters from a randomisation technique. Upper panels (a), b)): prominence apex at 82.3 Mm. Middle panels (c), d)): NE leg at 65.1. Lower panels (e), f)): SW leg at 65.1 Mm. Left panels (a), c), e)): first oscillatory train. Right panels (b), d), f)): second oscillatory train.