This command is very effective in proving complex sequential circuits, when
the internal state of the circuit quickly propagates to $equiv cells.
However, this command uses a weak definition of 'equivalence': This command
proves that the two circuits will not diverge after they produce equal
outputs (observable points via $equiv) for at least <N> cycles (the <N>
specified via -seq).
Combined with simulation this is very powerful because simulation can give
you confidence that the circuits start out synced for at least <N> cycles