To make an instance of a module, means to define a variable that will be acting as that module. So in line cshaper shaper 'Circle' 10, we prepend the module name 'shaper', with the instance name 'cshaper', that will be the instance variable, or simply, the instance. This variable differs from other Tyl variables. It does not participate in assignment statements and can not be passed as an argument to a function, but on the other hand, it have all module variables, and can operate all module functions, by the format instance.variable and instance.function respectively.

In line print cshaper.shape, shape variable of shaper module was accessed with cshaper instance, and in line cshaper.draw, draw function of shaper module was called with cshaper instance. Note that unlike single modules that their one and only module is recognized and active anywhere in the code, instance modules rules of scoping are the same as other variables.

More on working with dynamic system modules can be found in Dynamic System Modules Reference