  This report surveys results on distributed systems comprising mobile agents
that are identical and anonymous, oblivious and interact solely by adjusting
their motion according to the relative location of their neighbours. The agents
are assumed capable of sensing the presence of other agents within a given
sensing range and able to implement rules of motion based on full or partial
information on the geometric constellation of their neighbouring agents. Eight
different problems that cover assumptions of finite vs infinite sensing range,
direction and distance vs direction only sensing and discrete vs continuous
motion, are analyzed in the context of geometric consensus, clustering or
gathering tasks.
