13w37b fixed portals not rendering when next to each other. It also fixed portals being able to be crossed/overlapped. The problem now is since portals render again when in these arrays, it's that much harder to see if stuck inside them. (When I made this yesterday, I tried going through in Survival. The portal won't start teleporting you until you leave portal blocks, but the iron bars kept me from leaving. Plus, you can't pause or open chat while inside, so you're essentially trapped. I had to piss off the pigmen so they'd kill me.)