Torsional oscillations of a pore. Upper panel: angular rotation oscillations of the two lobes of the magnetic pore measured by following the edges of the structure in maps of circular polarisation in the Fe I 617.3 nm line using IBIS data. Bottom panel: schematic representation of the conclusions of the above measurements on the propagation of the m = 1 torsional Alfvén mode in the observed pore. Adapted from Stangalini et al. (2021b).