Equivalent width of the He ii λ4686 line in 1989 and simultaneous C iv blue edge wind variability (top, taken from Henrichs 1991) plotted along with the derived properties of the blobs with the symbol size proportional to the optical thickness (bottom). The vertical axis denotes the longitude of each blob as derived from the fits. The length of the connecting solid lines indicates the lifetime of the blobs. The linear trend is caused by the rotation.