One theory is that it would pull apart the fabric of time, considering you can not lay a portal attop of another without damaging space fabrics. Therefore, this would create a paradox, or black hole. But since this doesn’t seem to be illustrated, the best guess I can give is that the portals would pass through and reflect each other’s world, like two mirrors in front of one another.
As the portals got closer to each other, the left side of your body would get mashed up against the right side. Different parts of your body would attempt to occupy the same space, and just end up crushing each other. You’d get crushed into a red paste, evenly distributed through the diameter of the portals.
If you could somehow see inside the portals (which you can’t, without occupying that space and therefore crushing yourself) it would just appear to be one long endless tunnel.
You’d be infinitely spread through the portals, so to you, it would appear that you were infinitely long, like looking into a hall of mirrors, but it doesn’t reflect. Along with that, there would be multiple versions of yourself. Because there would be one of you that goes through the orange portal, one of you that goes through the blue portal, and the rest of you that would go through the other side of the top and bottom portals. To anyone looking on, it would appear you were crushed, and you would be, but not in the way they see it. You would infinitely collide with yourself over and over again, to the point where you crush yourself. If that didn’t kill you, there would be no air, or very little of it (it depends on if the portals touch completely). If that didn’t kill you either, you would simply die by extreme temperature. If you are in an infinite loop of portals, you really are only taking of area of 2 Dimensions. Depth would not exist, so you would (probably) burn up because of the heat collapsing. I haven’t even talked about the fact that this could probably create a black hole