Original Post — Direct link
When you select a bunch of blocks and then either copy or paste them, you can select symmetry to flip it in one axis. However, symmetry apparently doesn't work on items like arrow signs or lights, resulting in this:

As you can see, the arrows are pointing the wrong way, and so are the lights. Oops...

Still, it looks like a cool effect if used properly. Gonna have to set up some glitched blocks to keep as macroblocks.
about 4 years ago - UBI-Froggard - Direct link
Thanks for the report and image. Will pass this over to the game team.