  We consider a tiling model of the two-dimensional square-lattice, where each
site is tiled with one of the sixteen Wang tiles. The ground states of this
model are all quasi-periodic. The systems undergoes a disorder to
quasi-periodicity phase transition at finite temperature. Introducing a proper
order-parameter, we study the system at criticality, and extract the critical
exponents characterizing the transition. The exponents obtained are consistent
with hyper-scaling.
