  We investigate dynamics of the cellular automaton rule 142. This rule
possesses additive invariant of the second order, namely it conserves the
number of blocks 10. Rule 142 can be alternatively described as an operation on
a binary string in which we simultaneously flip all symbols which have
dissenting right neighbours. We show that the probability of having a
dissenting neighbour can be computed exactly using the fact that the surjective
rule 60 transforms rule 142 into rule 226. We also demonstrate that the
conservation of the number of 10 blocks implies that these blocks move with
speed -1 or stay in the same place, depending on the state of the preceding
site. At the density of blocks 10 equal to 0.25, the rule 142 exhibits a
phenomenon similar to the jamming transitions occurring in discrete models of
traffic flow.
