  We present a probabilistic cellular automaton (CA) with two absorbing states
which performs classification of binary strings in a non-deterministic sense.
In a system evolving under this CA rule, empty sites become occupied with a
probability proportional to the number of occupied sites in the neighborhood,
while occupied sites become empty with a probability proportional to the number
of empty sites in the neighborhood. The probability that all sites become
eventually occupied is equal to the density of occupied sites in the initial
string.
