The paper by Rakovszky and Khemani explores the construction of classical and quantum low-density parity check (LDPC) codes from a physical perspective, focusing on constructive approaches. They introduce a general framework for systematically constructing codes with various features on generic Euclidean and non-Euclidean graphs. The authors highlight the importance of product constructions in coding literature, such as the tensor product, hypergraph product, balanced product, and check product, and analyze them from a physical viewpoint. They introduce a new cubic product and combine these with ideas from Part I, which discusses gauging and Higgsing. The paper demonstrates the utility of this approach by showing that using the one-dimensional Ising model as a starting point, a wide range of classical and quantum phases of matter can be systematically produced, including fracton phases and SPT phases with generalized symmetries. Additionally, they construct new Euclidean models, such as a topological order enriched by translation symmetry and an exotic fracton model combining fractal spin liquid and toric code excitations. The paper also reviews existing constructions of good qLDPC codes and locally testable classical codes, and discusses the relationship between quantum code distance and classical energy barriers.The paper by Rakovszky and Khemani explores the construction of classical and quantum low-density parity check (LDPC) codes from a physical perspective, focusing on constructive approaches. They introduce a general framework for systematically constructing codes with various features on generic Euclidean and non-Euclidean graphs. The authors highlight the importance of product constructions in coding literature, such as the tensor product, hypergraph product, balanced product, and check product, and analyze them from a physical viewpoint. They introduce a new cubic product and combine these with ideas from Part I, which discusses gauging and Higgsing. The paper demonstrates the utility of this approach by showing that using the one-dimensional Ising model as a starting point, a wide range of classical and quantum phases of matter can be systematically produced, including fracton phases and SPT phases with generalized symmetries. Additionally, they construct new Euclidean models, such as a topological order enriched by translation symmetry and an exotic fracton model combining fractal spin liquid and toric code excitations. The paper also reviews existing constructions of good qLDPC codes and locally testable classical codes, and discusses the relationship between quantum code distance and classical energy barriers.