  We present Very Large Array images of a "Double-Double Radio Galaxy", a class
of objects in which two pairs of lobes are aligned either side of the nucleus.
In this object, B0925+420, we discover a third pair of lobes, close to the core
and again in alignment with the other lobes. This first-known "Triple-Double"
object strongly increases the likelihood that these lobes represent mutiple
episodes of jet activity, as opposed to knots in an underlying jet. We model
the lobes in terms of their dynamical evolution. We find that the inner pair of
lobes is consistent with the outer pair having been displaced buoyantly by the
ambient medium. The middle pair of lobes is more problematic - to the extent
where an alternative model interpreting the middle and inner "lobes" as
additional bow shocks within the outer lobes may be more appropriate - and we
discuss the implications of this on our understanding of the density of the
ambient medium.
