Embodiments that create parent-child relationships for reuse of 1×N building blocks in a closed-loop 1×N system are disclosed. Some methods comprise generating a representation of an IC design, inserting a first 1×N building block into the representation, and creating an association between the first 1×N building block and a second 1×N building block. The association enables the first 1×N building block to inherit alterations of attributes of the second 1×N building block and enables unique alterations of attributes of the first 1×N building block which differ from the second 1×N building block. Further embodiments comprise an apparatus having an equivalency determiner to determine a logical equivalence between a two 1×N building blocks, an attribute creator that creates a set of attributes and enables one of the 1×N building blocks to inherit parent attributes and comprise child attributes.