IntermediateRedstone
How to make hidden doors in Minecraft
Build a painting door for a hideout in two minutes, or a flush piston door when you want no visible gap at all.

A Painting is a framed artwork that you hang on a wall.
It is made with the Crafting Table from 8 × Stick and Black Wool (or another variant).
Eight sticks around a block of wool make one. When placed, it picks a random motif that fits the free wall space, so make room for larger ones. Paintings also hide hidden doors and storage nicely.
8 × Stick + Any of #wool → Painting
// Slots with several items cycle through every accepted option.
Build a painting door for a hideout in two minutes, or a flush piston door when you want no visible gap at all.
At the Crafting Table: 8 × Stick and 1 × Black Wool (or another variant) give 1 × Painting. Sold by Villager: Shepherd (Master).
It decorates walls with random artworks.