Piston

Pistons are blocks capable of pushing most blocks, depending on the direction they are facing.

Sticky Pistons are similar to pistons; the difference is that they can pull blocks as well as push them.

Natural generation
Three 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 (head) extends outward by one block, which can push up to 12 blocks in a line with it. Any entities in the path of the extending head will be pushed with the blocks. If there is no place for the entities to go, the block will push inside the mob, suffocating it if the block is not transparent.

When a piston loses power, it will retract by simply pulling its head back, unless it is a sticky piston, in which case it will also pull the block in front of the head.

Sticky pistons only stick to a block 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.

A piston that pushes a slime block will bounce any entity that it displaces in the direction the piston is facing.

Pushing Blocks
Pistons will not push blocks into the Void or the top of the map. They also cannot push more than 12 blocks. In either case, the piston simply will not extend.

Pistons can push most blocks, exceptions are listed below:

Pistons also will not move blocks that are "attached to a block", as they will be detached and drop as an item. Exceptions include:


 * s: as long as their hinged side remains attached to a solid block in their new position.
 * : as long as they remain on top of a solid block in their new position. Rails will re-orient themselves after being pushed just as they do when placed manually.

Powering Pistons


Pistons can be powered in various ways:
 * If a redstone wire goes is in a line shape towards the piston, as the wire will 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. However, the piston won't extend or retract until it receives a block update.
 * A repeater cannot transfer power through a piston, as pistons are a transparent block.
 * An upwards-facing piston can't be powered by the block above it, unless it is extended.

Slime Blocks
When a slime block is pushed or pulled by a piston, it will attempt to move in the same direction all adjacent blocks that can be pulled by a sticky piston. These blocks may in turn push other blocks. For example, a Slime Block sitting on the ground will attempt to move the ground block underneath itself, which will in turn have to push additional ground blocks in the direction of motion just as if it were being pushed directly by a piston.

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 will ignore the immobile block. But if an adjacent block could be moved but is prevented by the presence of an immobile block, the slime block will be 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.

Trivia

 * In the future, sticky pistons may also be used for pushing Spike Blocks instead of having a spiky piston.
 * When blocks are pushed by a piston, they are momentarily non-solid and cause any players/items on the moving block to fall through the moving block.
 * When toggled between on and off rapidly with a gravity affected block (such as sand) above it, a piston will eventually break the block, which can be picked up as a resource. However, gravel will never break into flint.
 * If you push a burning block, the block will be put out. If you push a row of burning blocks, they will all stay on fire except for the farthest one.
 * If a sticky piston blocks a redstone wire vertical connection that is the same one giving the piston power, it will extend and retract over and over very quickly, making it possible to build a simple clock.
 * In creative mode, if you break a block while it is being pushed by a piston, the particles will be particles of a piston
 * You must be in creative mode so that the block is broken before it stops moving
 * Although having a wooden top, Pistons and Sticky Pistons are not flammable.
 * If a Sticky Piston pushes a block of redstone upwards, it will not retract when turned off, due to piston quasi-connectivity.
 * In console versions of Minecraft, it is possible to go a few blocks past the build limit on the side of the End by pushing blocks with a piston.
 * Pistons are only semi-opaque as light can pass through it. It is likely related to the fact that an extended piston has two non solid transparent parts which let light pass.