  We find the three-dimensional gravity dual of a process in which two clouds
of (1+1)-dimensional conformal matter moving in opposite directions collide.
This gives the most general conformally invariant holographic flow in the 1+1
dimensional boundary theory in terms of two arbitrary functions. With a
suitable choice of the arbitrary functions the process can be interpreted as an
opaque collision of two extended systems with central, fragmentation and
interaction regions. Comparison with classical gluon field calculations relates
the size of the system with the saturation scale.
