Temporal evolution of Ca ii 854.2 nm spectra in the blue and red patches (blue and red circles, respectively). Columns 1 and 2 correspond to Stokes I, while Cols. 3 and 4 correspond to Stokes V. Time increases from top to bottom and from left to right. The scaling of the y-axis in normalised intensity units is between (0.2,0.7) and (− 0.05,0.05) for the two Stokes parameters. The profiles come from the pixel with the highest average intensity between −300 and −400 mÅ.