  Peripheral one-tube model has shown to be a nice tool for dynamically
understanding several aspects of ridge structures in long-range two-particle
correlations, observed experimentally and obtained also in our model
calculations using NexSPheRIO code. Here, we study an extension of the model,
to initial configurations with several peripheral tubes distributed randomly in
azimuth. We show that the two-particle correlation is almost independent of the
number of tubes, although the flow distribution becomes indeed strongly event
dependent. In our picture, the ridge structures are causally connected not only
in the longitudinal direction but also in azimuth.
