Connecting modules. Figure (a) shows a simple phosphorylation and dephosphorylation cycle. The cycle is converted to a module by placing all the components inside a module box and declaring the proteins as interfaces. The interface items are shown as small pins around the module box. The interface items can be used to connect one module to another, as shown in (b). In figure (b), the module shown in (a) is copied and pasted three times. The three modules are connected together to form an oscillating protein network . The orange connections between the modules' interface pins indicate that the connected components are the same. For example, the phosphorylated protein in the first module is the molecule as the kinase in the second module. In other words, modules are connected by defining the shared components.