If I posted a pic of a PCB, could you tell me where the ground is?

I am wiring my own arcade twin-stick controller and I cannot seem to find the ground on the controller's PCB. I was wondering, if I posted a pic of the PCB, would you guys be able to tell me where the ground is so that I can touch the wires connected to all the different buttons and have it activate a button press? Thanks a lot.

Someone would definatly be able to help you out!

Actually, I just realize that on a controller any ground point works the same as any other ground, meaning I know how to make it work (unless I just randomly found the ground point by chance )