The Meaning of Life, the Universe, and Everything.
Let me start by saying that when I started playing this game I used to get infuriated with redstone, something as simple as continuing a current with torches confused me, and I swore off the mechanic all together. That was a very long time ago and countless contraptions later I've grown comfortable playing with redstone. Despite my frustration I have NEVER watched a youtube video on it or used a tutorial to bring my desire to life so you'll have to forgive me if you've seen a similar design before, you think it's a sad attempt, or I have no clue what to call that collection of repeaters that I've thrown together to make it work- that's all I know them as. All the same, now that I've started surfing this forum, I've seen some people asking about different doors and staircases so I figured I'd post a couple of mine here for people to use as they will. I hope you enjoy.
My first contribution is a 2x2 piston door that opens and closes into the floor allowing for a 1 wide wall with no visible redstone. For simplicity I've put the lever in the middle of the floor but obviously only the input location and that it is a toggle is important.