Percentage of LP, P, as a function of μ = cos i, where i is the angle between the normal to the CC and a given direction (see ST85 and our Fig. 3). Red and blue boxes are drawn for the measured linear polarization degree in the 2–8 keV for the soft and hard states, correspondingly, for different BH sources (source names are indicated by arrows next to the corresponding μ). The vertical width of these boxes corresponds to the error bars of the IXPE measurements.