  Artificial spin ice systems, namely lattices of interacting single domain
ferromagnetic islands, have been used to date as microscopic models of
frustration induced by lattice topology, allowing for the direct visualization
of spin arrangements and textures. However, the engineering of frustrated ice
states in which individual spins can be manipulated in situ and the real-time
observation of their collective dynamics remain both challenging tasks.
Inspired by recent theoretical advances, here we realize a colloidal version of
an artificial spin ice system using interacting polarizable particles confined
to lattices of bistable gravitational traps. We show quantitatively that
ice-selection rules emerge in this frustrated soft matter system by tuning the
strength of the pair interactions between the microscopic units. Via
independent control of particle positioning and dipolar coupling, we introduce
monopole-like defects and strings and use loops with defined chirality as an
elementary unit to store binary information.
