Thickness gradation

Hi, I'm pretty much a noob to Grasshopper and for product design project, i made this wireframe generator and I'm having hard time to manage the thickness of the exoskeleton:

I want it ti be thick at the center of the geometry and further it gets from this point the thinnest it gets.

I guess it's retty simple with the distance but I don't get it. Could somebody help me or give me a link to some tutorial?

Thanks a lot!!