Minecraft wiki entry for Hiding_chests, associated text: A "hipster door" (youtube/X3LbkSTjR7I?t=10m3s) is a door that can be disguised as part of the wall and be opened via slime blocks and two sticky pistons. Chests are perfect in this situation because they are non-movable blocks, so they will not be pulled down by the slime blocks. (Java edition only)