irregular short structures in the H$\alpha$ image of Fig. \[fig:overview\_azimuth\].

In the sunspot, the transition region is very low, 1 Mm above the quiet photosphere [and roughly 2 Mm above the local height of continuum optical depth unity]{}. so that all four spectral lines are formed mostly at the same height. The angle between the field vector and the $\tau=1$ surface is large. In the area where $x < 51$ Mm we see intrusions of high mass density sticking into the low-density corona, and the $\tau=1$ surface follows these mass intrusions. We speculate that these could be Type I spicules as simulated before in 2D [e.g., @2006ApJ...647L..73H], but this is impossible to confirm without analyzing a time series.

Now we turn our attention to the long loop-like structure between $X = 51$ Mm and $X = 68$ Mm [in Figure \[fig:fibrils\].]{} The magnetic field vector and the $\tau=1$ height curve of H$\alpha$ are parallel to each other for a large fraction of the loop. It is not shown in the figure, but this is true to a lesser extent for the other lines, which all exhibit jumps in their formation height. We analyze a number of other fibrils not illustrated 