This post will show you how to make a secret door using paintings!
First, find a wall. Then, break 2×2 hole in the wall. Put trapdoors on both sides of the wall. Then, sneak while
holding the painting and looking at the side of the trapdoor, and place the painting. You can break the painting until you get the one you want, or you can keep it. Now if you step in the right spot, you can walk through the painting into a secret room you build!