Talk:Observer/@comment-26821502-20160504073959/@comment-25014034-20160504095227

That is correct. It refers to a concept in Minecraft called 'BUD' (Block Update Detection). You can try it out to- Take a Piston and set the block next to it on Fire. The Piston will activate.

Darth wikia25 ( Contact Me ) 09:52, May 4, 2016 (UTC)