I'm playing Skyblock, and after getting my cobblestone generator working, I'm planning on a total revamp of my entire little sky-island. However, I want to make certain that I don't lose important stuff (like dirt), so I want to build a safety net under my island.
So I'm left with a problem very similar to this one: "Is it possible to lay a block adjacent to another without looking at the face of the existing block?", except I need to build down so shift doesn't help.
How can I do this?
Oh, and there is no ground, it's just void beneath me, so dropping sand or gravel is out of the question (that, and I have no sand or gravel to drop).