365791.fig.006a
(a)
365791.fig.006b
(b)
365791.fig.006c
(c)
365791.fig.006d
(d)
365791.fig.006e
(e)
365791.fig.006f
(f)
Figure 6: (a-b) Two flocks head toward the world centre from opposing directions. (c) They avoid each other at first. But soon they closely interact again. (The images were adjusted to fit both flocks, the zoom was slightly increased once for capturing (d–f)).