Systematic construction of gapped nonliquid states

This paper use 2+1D topological orders, or domain walls between 3+1D topological orders, to construct the microscopic cellular structure of a 3+1D gapped non-liquid state by glueing those 2+1D topological orders, or domain walls, together. The author further shows that this construction could produce gapped non-liquid states with fractal-like excitations.