Observation of coronal waves in the Doppler velocity of a coronal emission line by COMP from Threlfall et al. (2013). The diagram has time in abscissas and the coordinate z, along the loop and parallel to the magnetic field, in ordinates. Among the many visible dislocations, two have been labeled. The closed curve (that could represent the monodromy) encloses an edge dislocation, while the straight segment follows a possible gliding dislocation.