What if you try to sandwich a cube between two portals?

Full Video: https://www.youtube.com/watch?v=zDAE9A_1NA4 What if you try to sandwich a cube between two portals? Does the cube disappear? Do the portals bounce or stop? Or something else? Imagine instead that you extend a piston through the blue portal. Eventually it comes back and hits itself from behind. The piston can't keep extending into the portal because there is no "inside" of the portal - "inside" the blue portal is "outside" the orange portal, and vice versa. At this point one of three