Left: a scalar wave carrying a dislocation is imaged as the real part of the function (y + ix)e^ix in the plane (x, y). Only a zoom over the region around the dislocation is shown. Three monodromies are drawn, two as circumferences centred at the dislocation and one that does not enclose it. The phase change along these paths is 2π if the singularity is enclosed, but zero if it is not. Right: the phase along the three monodromies. Because of its shorter length, the phase undergoes a more rapid change for the inner monodromy enclosing the dislocation.