2D maps showing the column densities of O VI. Panel 3a shows the projections for the R32-AL simulation along the y-axis for down-the-barrel images (top) and along the x-axis for edge-on (bottom). The same for the model R32-TR in panel 3b. From left to right, the plots display C II column densities at t = 0.2, 1.2, 2.2 and 3.2 Myr (or t/t_cc = 0.2, 0.9, 1.7, 2.5) respectively. We see that the contrast among cloud and wind material is less for O VI than C II and C IV. O VI traces the outer layers of the cloud, which are well mixed with the wind, so it also covers a more extended area in both down-the-barrel and edge-on projections than the cold and intermediate ions.