  We show that dynamic, feed-back controlled optical traps, whose positions
depend on the instantaneous local configuration of particles in a
pre-determined way, can stabilise colloidal particles in finite lattices of
${\it any}$ given symmetry. Unlike in a static template, the crystal so formed
is translationally invariant and retains all possible zero energy modes. We
demonstrate this ${\it in-silico}$ by stabilising the unstable two-dimensional
${\it square}$ lattice in a model soft solid with isotropic interactions.
