Three-color image of [C II] velocity channels of the southern Veil shell. Blue is the velocity channel v_LSR =0−2 km s⁻¹, green v_LSR = 4−6 km s⁻¹, and red v_LSR = 8−10 km s⁻¹. Arrows indicate structures that resemble fingers formed due to the Rayleigh-Taylor (RT) instability. One of these, labeled “possible pillar”, might also be formed by an overdensity encountered by the expanding shell and subsequently sculpted by the strong stellar radiation field, as it also is observed in CO (cf. Fig. 1c). The spectra shown in Fig. 20 were extracted towards the areas indicated by the numbered circles.