It was already hard enough to figure out how to make a nether portal in a superflat world, but with a recent change in Minecraft 1.10, it's even harder! Watch this to figure out how to make that ...

This tells the encoder to only use 12 columns at a time (it defaults to 64), and to use a Y level of -60, as I'm testing this in a superflat world. This is what the above looks like in-game: ...