Be aware that the PGcmgui uses module names to save configurations. This is a classic dataflow example. This one is tricky. Think about it carefully on paper before starting. One part computes the fibonacci series with an adder and a switch that feeds back into the adder.
Proper initialization is the key.
The other part implements has a loop counter that controls the number of iterations of the fibonacci series part of the dataflow graph by controlling its switch. For the loop counter, try using an increment module, an inequality, and a switch. If you want to be really clever, make it reentrant. Think of an interesting calculation and create a dataflow program for it using the components you have built. You should be prepared to demonstrate your working application, explain your design and code, and answer questions.