Details of the formation of the Hα line within a special multi-thread configuration of the Model3_6000 (see Fig. 16, top) at the position 25. The first plot at the upper left corner represents the outgoing Hα profile from the last thread in the configuration. In the rest of the first column, we plot the same Hα profiles as in the fourth column in the row above and also the optical thickness profiles (red dashed line) of the threads where the respective absorption occurs. Values of the optical thickness are given on the right-hand side with ranges of from 0 to 1. The second column shows Hα profiles after the respective partial absorption. The third column displays outgoing Hα profiles from the threads themselves (threads are indicated by numbers) and the fourth column shows the sum of columns two and three. The perpendicular dash-dotted line indicates the zero-velocity Hα line centre wavelength. The LOS velocities of each thread are indicated by “v =” in km s^-1. The derived Doppler velocities of all Hα profiles in the fourth column are indicated by “DopplV =” in km s^-1.