  Gamma ray bursts are often modelled as jet-like outflows directed towards the
observer; the cone angle of the jet is then commonly inferred from the time at
which there is a steepening in the power-law decay of the afterglow. We
consider an alternative model in which the jet has a beam pattern where the
luminosity per unit solid angle (and perhaps also the initial Lorentz factor)
decreases smoothly away from the axis, rather than having a well-defined cone
angle within which the flow is uniform. We show that the break in the afterglow
light curve then occurs at a time that depends on the viewing angle. Instead of
implying a range of intrinsically different jets - some very narrow, and others
with similar power spread over a wider cone - the data on afterglow breaks
could be consistent with a standardized jet, viewed from different angles. We
discuss the implication of this model for the luminosity function.
