FIGS. 8 a and 8 b are a partial cross-sectional views of the assembled stylus 5 showing in more detail the relative positions of the ferrite rod 153, the coil 45, the split washer 157 and the nib 159 in these ???unclicked??? and ???clicked??? states respectively, and illustrating magnetic field lines 180 passing from the end of the ferrite rod 153 around the coil 45.