3 wide Minecraft flush secret staircase schematic?

I've been sitting in front of my PC for hours trying to build a 3 block hidden staircase with pistons. I give up slowly because it always has errors and therefore does not work. Now I wanted to ask here if someone has a staircase which leads into a lower floor and is completely covered. If someone had a schematic download would be the mega nice…

Look Mumbo Jumbo on YT, he has all the Redstone creations you can wish for.