1. A non-transitory memory medium that stores program instructions for creating a graphical program, wherein the program instructions are executable to perform: assembling a first plurality of graphical program elements in a graphical program in response to first input, wherein the assembled first plurality of graphical program elements comprise a plurality of interconnected graphical program elements, wherein the assembled first plurality of graphical program elements have a first model of computation; displaying a structure in the graphical program in response to second input, wherein the structure comprises an interior portion, wherein the structure indicates use of a second model of computation for graphical program elements comprised within the interior portion of the structure, wherein the second model of computation is different than the first model of computation; and assembling a second plurality of graphical program elements within the interior portion of the structure in response to third input, wherein the assembled second plurality of graphical program elements comprised within the interior portion of the structure have the second model of computation; wherein the graphical program is executable to perform a function.