  We propose an algorithm for creating stable, ordered, swarms of active
robotic agents arranged in any given pattern. The strategy involves suppressing
a class of fluctuations known as "non-affine" displacements, viz. those
involving non-linear deformations of a reference pattern, while all (or most)
affine deformations are allowed. We show that this can be achieved using
precisely calculated, fluctuating, thrust forces associated with a vanishing
average power input. A surprising outcome of our study is that once the
structure of the swarm is maintained at steady state, the statistics of the
underlying flow field is determined solely from the statistics of the forces
needed to stabilize the swarm.
