  Pairs of numerically computed trajectories of a chaotic system may coalesce
because of finite arithmetic precision. We analyse an example of this
phenomenon, showing that it occurs surprisingly frequently. We argue that our
model belongs to a universality class of chaotic systems where this numerical
coincidence effect can be described by mapping it to a first-passage process.
Our results are applicable to aggregation of small particles in random flows,
as well as to numerical investigation of chaotic systems.
