Spatial distribution of measured fibril oscillation periods and LOS-POS phase differences. Each symbol marks the coordinates of the oscillation point. The triangular symbols mark the points where an oscillation is detected in both v_POS and v_LOS. The size of the triangular symbols is proportional to their average period. The colour-coding of yellow, orange, and red represents the absolute values of the phase difference between the v_LOS and v_POS oscillations where their period is correlated. The coordinates of the oscillations that do not have a clear correlation between their ${\overline{P}}_{\mathrm{POS}}$ and ${\overline{P}}_{\mathrm{LOS}}$ are shown with grey triangles. The orientation of the triangular symbols shows the perpendicular direction to the cuts (Fig. 1f) across the bright fibrils. The cross symbols mark the points where an oscillation is detected in the POS direction but not in the LOS direction. The filled white contour lines indicate areas in the photosphere with magnetic concentrations, where the footpoints of the fibrils are located.