Making new node class

Is it possible to make GoRoundedRectangle be gradient?
I cant not find to make it gradient and How do I make my own Class like GoInstrument? I have to make node more graphical.
Can you give me some information? Example code could be better to understand.

You might find the LinearGradientRoundedRectangle class in the Demo1 sample useful. There are other examples in the User Guide, demonstrating non-linear gradients with different shapes. See page 50.