Physical properties of the cross-cuts marked in Fig. 3. The left column shows the intensity-over-time variations of the cuts at the Ca II K nominal line centre. The oscillation in the POS is marked by dotted red curves. The middle and right columns display the temperature and v_LOS variations of the cuts as a function of time in the chromosphere (log(τ_500 nm) = −4.31). The POS oscillation is overplotted on these images as well. Length zero on the y-axis is where the cuts are marked by numbers in Fig. 3. The vertical line (|) symbols, marked on the curves in the left column, show the specific times of the fibril’s evolution that are displayed in Fig. 3.