Computation-friendly shape grammars

NP-hardness of parametric subshape recognition for an arbitrary number of open terms is proven. Guided by this understanding of the complexity of subshape recognition, a framework for computation-friendly parametric shape grammar interpreters is proposed, which is further detailed by a sub-framework over parametric two-dimensional rectangular shapes. As both the proof of NP-hardness and rectangular sub-framework invoke elements in graph theory, the relationship between shape and graph grammars is also explored.