  An algorithm for perfect simulation from the unique solution of the
distributional fixed point equation $Y=_d UY + U(1-U)$ is constructed, where
$Y$ and $U$ are independent and $U$ is uniformly distributed on $[0,1]$. This
distribution comes up as a limit distribution in the probabilistic analysis of
the Quickselect algorithm. Our simulation algorithm is based on coupling from
the past with a multigamma coupler. It has four lines of code.
