Fig. 8
From: Co-evolutionary dynamics in social networks: a case study of Twitter
a An initial network that includes a directed cycle. A sequence of TRF events can transform this cycle to a clique, meaning that the corresponding users gradually form a tightly knit community. b A hierarchical initial network. A sequence of TRF events can transform this multi-layer hierarchy into a two-layer hierarchy in which each sink node is directly followed by a set of other nodes (its “sphere of influence”), while each non-sink node follows at least one sink node