Inspiringly beautiful video of cloud-to-ground lightning –
You can see all steps of lightning. First the stepped leader (clound-t-ground), second the upward leader (from tower), third the attachment between these two leaders, 4th the RETURN STROKE (the main stroke of a discharge) and after, the subsequent strokes.
The capillary-like pattern of the stepped-leader seems particularly striking(npi), wikipedia expounds –
The negative charged leaders, called a “stepped leader”, proceed generally downward in a number of quick jumps, each up to 50 meters long. Along the way, the stepped leader may branch into a number of paths as it continues to descend. The progression of stepped leaders takes a comparatively long time (hundreds of milliseconds) to approach the ground. This initial phase involves a relatively small electric current (tens or hundreds of amperes), and the leader is almost invisible compared to the subsequent lightning channel.