  Kerr geometry has twofoldedness which can be cured by a truncation of the
`negative' sheet of metric. It leads to the models of disk-like sources of the
Kerr solution and to a class of disk-like or bag-like models of the Kerr
spinning particle. There is an alternative way: to retain the `negative' sheet
as the sheet of advanced fields. In this case the source of spinning particle
is the Kerr singular ring which can be considered as a twofold "Alice" string.
This string can have electromagnetic excitations in the form of traveling waves
generating spin and mass of the particle. Model of this sort was suggested in
1974 as a "microgeon with spin". Recent progress in the obtaining of the
nonstationary and radiating Kerr solutions enforces us to return to this model
and to consider it as a model for the light spinning particles. We discuss here
the real and complex Kerr geometry and some unusual properties of the
oscillating solutions in the model of "Alice" string source.
