  We review some recent investigations of the 3d plaquette Ising model. This
displays a strong first-order phase transition with unusual scaling properties
due to the size-dependent degeneracy of the low-temperature phase. In
particular, the leading scaling correction is modified from the usual inverse
volume behaviour 1/L^3 to 1/L^2. The degeneracy also has implications for the
magnetic order in the model which has an intermediate nature between local and
global order and gives rise to novel fracton topological defects in a related
quantum Hamiltonian.
