  Soliton rain is a bunch of small soliton pulses slowly drifting nearby the
main pulse having the period of a round trip. For Er-doped fiber laser
mode-locked by carbon nanotubes, for the first time, we demonstrate both
experimentally and theoretically a new type of polarization attractors
controllable by the vector soliton rain. With adjusting the pump power, vector
soliton rain takes the form of pulses with rotating states of polarization
which enable transforming slowly evolving trajectories on the Poincar\'e sphere
from the double-scroll spiral to the circle. The obtained results on
controlling complex multisoliton dynamics can be of interest in laser physics
and engineering with potential applications in spectroscopy, metrology, and
biomedical diagnostics.
