1. A computer implemented method of graphically defining a formula, said method comprising: displaying a graphically defined formula comprising one or more graphically connected graphical objects that graphically define the formula; selecting one or more of the graphical objects to be grouped into a new component object; determining the number of connections that provide an input to the selected objects; determining the number of connections that provide an output from the selected objects; determining a graphical definition of the formula, where the selected objects are replaced with a graphical representation of the new component object having a number of inputs based on the determined number of connections that provide an input and a number of outputs based on the determined number of connections that provide an output, one of more of the connections inputting to the selected objects from non-selected objects are replaced with one or more connections connecting to the input(s) of the new component object and one of more of the connections outputting from the selected objects to the non-selected objects are replaced with one or more connections connecting from the output(s) of the new component object; determining a logical definition of the formula which non-graphically describes the functionality of the formula represented by the graphical objects in the graphically defined formula based on the graphically connected graphical objects and the selection of one or more of the graphical objects, the logical definition of the formula excluding information necessary to display the graphically defined formula, wherein the selected objects are retained in the logical definition; and determining the input/output properties of connections that connect to the selected objects, and providing each input of the new component object with the properties of the corresponding connection inputting the selected objects and providing each output of the new component object with the properties of the corresponding connection outputting from the selected objects.