Recall that a function can be thought of as a machine which takes an input in (say x) and then depending on what that input is, it returns an output (say y) by some predefined rule (say f). The graph ...

I coded the demo program using C#, but you shouldn't have too much trouble refactoring my code to another language such as Visual Basic or Python ... ("Creating a 3-input, 4-hidden, 2-output NN"); ...