Embodiments that design integrated circuits using a closed loop 1×N methodology are disclosed. Some embodiments create a physical design representation based on a behavioral representation of a design for an integrated circuit. The behavioral representation may comprise RTL HDL with one or more 1×N building blocks. The embodiments may alter elements of the 1×N building block by using logic design tools, synthesis tools, physical design tools, and timing analysis tools. Further embodiments comprise an apparatus having a viewer and a 1×N compiler. The viewer may generate displays of behavioral representations of 1×N building blocks, with the behavioral representations comprising RTL definitions. The 1×N compiler may create physical design representations of the 1×N building block and create behavioral representations from the physical design representations, wherein the physical design representations have elements altered by one or more tools of a tool suite.