I'm writing a children's book where there is a force field over a park. I need a way for my characters to get through the force field without them totally shutting it down. I'm thinking something like a large ring (about the size of a hula hoop) that they can stick into the field that would somehow loop the energy around and keep the ring open and clear so they could get through. Is this possible? Can you think of another way? Thanks for your time and thoughts!