You can also do item shadowing whit just your main and off hands. First get some blocks to your main hand then hold Q then press F to transport the items to your off hand that will item shadow the items.
Listen, this video might have some hacked ways, but if its still entertaining, i would like it. If i saw a person making tetris in minecraft but cheat to get the items, i get it. Its hard to get ANY items, especially in the void.
@22:52 You should always build the corners when blocking yourself up in hardcore. I’ve died while afk blocked up exactly how you were here (thankfully not in hardcore) and I know a few others that have as well. I believe I heard something about this being fixed in a recent update or snapshot so it might not matter soon but personally I will still always fully block myself up corners included (3x3x4) when afk’ing just to be safe.