Piston

"Pistons push blocks, up to twelve of them in a row, when given a redstone signal. Flip the power on and the piston's head will extend outwards one block for a fraction of a second. Any entities in the path of the head will be pushed along with it, including the player, and if there's a slime block in front of the head then they'll be sproinged off instead. SPROINGGG!"

- Duncan Geere

A piston is a block capable of pushing movable blocks when given a redstone pulse.

A sticky piston can both push and pull movable blocks when given a redstone pulse.

Obtaining
A piston can be broken using any tool with equal efficiency, and always drops itself.

Natural generation
Three or four sticky pistons generate as part of each jungle temple.

Usage
Pistons are always placed facing towards the player. When powered, the piston's wooden surface (the "head") starts extending immediately, and pushes at most 12 blocks. The extension takes 2 game ticks, or 1 redstone tick (0.1 seconds). The piston makes a sound that can be heard within a 31×31×31 cube centered on the activating piston. Any entities in the path of the extending head are pushed with the blocks. If there is no place for the entities to go, the block pushes inside them, suffocating mobs if the block is not transparent when pushed into the eye height of the mob.

When a piston loses power, its head retracts. This retraction starts immediately, but lasts for 2 game ticks or 1 redstone ticks (0.1 seconds). A sticky piston also pulls the block attached to its head.

Sticky pistons stick to a block only when retracting, so a block next to the piston head can be pushed aside by another piston and sticky pistons cannot hold falling blocks horizontally against gravity. They also don't pull blocks after starting to push them. This can be done by giving the piston a short pulse, specifically shorter than 3 gameticks, or 1.5 redstone ticks (0.15 seconds, barring lag).

A piston that pushes a slime block bounces any entity that it displaces in the direction the piston is facing. In addition, when a slime block is moved by a piston, any movable blocks adjacent (not diagonally) to the slime block also moves. See the "usage" section below for more details.

Blocks that stick to walls (such as levers) can be placed on pistons or sticky pistons.

Limitations
Pistons can push most blocks, and sticky pistons can pull most blocks, except those listed in the table below. Sticky pistons simply leave a block behind if it cannot pull it.

Pistons cannot push blocks into the void or beyond the top of the map. They also cannot push more than 12 blocks. In these situations, the piston simply does not extend.

Pistons do not move blocks that are "attached to a block", as they detach and drop as an item.

Exceptions

 * : as long as they remain on top of a solid block in their new position, and that block isn't moving at the same time.
 * An exception is when the rail and block supporting it are on two parallel extended pistons at which the rail remains attached. Trying to move both on the same piston using slime blocks does not work, nor does moving them on perpendicular pistons (although the latter temporarily appears to work because of a bug ).
 * Rails re-orient themselves after being pushed, similar to when placed manually.

Powering pistons


Pistons can be powered in various ways:
 * If a redstone wire is in a line shape towards the piston, as the wire does not automatically curve to the piston.
 * Pistons can be powered by a powered block directly adjacent to them, whether it is strongly powered or weakly powered.
 * Pistons can be powered by a redstone torch directly adjacent to them.
 * Pistons can be powered by any powered block one block above and to the side, including the "activated space" above it (if a piston, both sticky and normal were to be facing up and a block of redstone placed on its head, it extends when powered, but doesn't retract when the power it receives from the side or back turns off). However, the piston won't extend or retract until it receives a block update. This property is called quasi-connectivity and can be used to make a BUD switch.
 * A repeater cannot transfer power through a piston, as pistons are a transparent block.
 * An upwards-facing piston can't be powered by a block above it, unless it is extended.

Slime blocks
When a slime block is pushed or pulled by a piston, while moving, adjacent blocks also move with the slime block, unless a non-piston movable block stops the blocks that are "grabbed" by the slime blocks. These blocks may in turn push other blocks, not just the blocks in the line in front of the piston. For example, a slime block sitting on the ground attempts to move the ground block underneath itself, which in turn has to push additional ground blocks in the direction of motion just as if it were being pushed directly by a piston.

Glazed terracotta is an exception; it does not move when adjacent slime blocks are moved.

The same occurs when a slime block is moved by an adjacent Slime Block. For example, a 2×2×2 cube of Slime Blocks may be pushed or pulled as a unit by a single piston acting on any of the blocks in the cube.

A slime block adjacent to a block that cannot be moved by pistons ignores the immobile block. But if an adjacent block could be moved but is prevented by the presence of an immobile block, the slime block is prevented from moving.

Slime blocks are not pulled by a non-sticky piston, nor are they moved if an adjacent (non-Slime) block is moved by a piston.

The maximum of 12 blocks moved by a piston still applies. For example, a 2×2×3 collection of Slime Blocks may be pushed or pulled by a sticky piston as long as no other movable blocks are adjacent to it.

A piston cannot move itself via a "hook" constructed of slime blocks, but self-propelled contraptions can be created with multiple pistons. For that, see the article Tutorials/Flying technologies.

Piston Head
The piston head is a technical block used as the second block of an extended piston. A block state defines whether it is a normal or a sticky piston head. It can be placed using the command or with the debug stick, though if not part of a proper piston, it disappears after receiving any block tick, such as when a block is placed next to it unless the player uses the debug stick.

Moving Piston
The moving piston is an unobtainable technical block that contains part of a piston head, and/or part of one or two blocks that the piston is carrying into or out of the grid cell (including blocks carried indirectly via slime blocks). Since moving blocks vary in how much of each grid cell they occupy, they can't be stored as normal blocks and are instead stored as block entities. It is overwritten with air, the piston head or the carried block at the end of the piston stroke; but if it is placed by a command and no piston is connected, it remains indefinitely.

It is invisible, non-solid, and cannot be broken without the use of commands or TNT. Although it is non-solid, fluids cannot pass through it. It also prevents players from building at its location. Mobs can see through it, but cannot walk through it. The game treats the block as a stone block when it comes to the player's footstep sounds, and as a missing texture block when it comes to the breaking animation.

Block entity
The moving piston has a block entity associated with it that holds additional data about the block.

Block data
In Bedrock Edition, pistons use the following data values:

Block states
The  and   blocks use following block states:

Trivia

 * When toggled between on and off rapidly with a gravity affected block (such as sand) above it, a piston can eventually break the block, which can be picked up as a resource. However, gravel broken this way never drops flint.
 * Mobs can spawn inside the piston head block.
 * Carpet can be placed on the piston extension block, and remains even if is replaced with a solid block using.
 * The piston head is invisible and non-solid when placed in Bedrock Edition with commands.
 * The piston extension cannot be placed by block placement commands, and immediately disappears in Bedrock Edition.