Piston

Pistons are blocks capable of pushing or pulling adjacent blocks, depending on the direction they face. The original version of this feature was a mod posted on the Minecraft Forums by Hippoplatimus. Pistons were added in version 1.7, as well as Sticky Pistons. Sticky Pistons added a use for Slimeballs. Pistons are slightly altered from the original version and they will not be called pistons. . One known difference from the mod's usage is that Pistons will not launch the player and other entities in the air. Pistons can't move Blocks like Chests, Noteblocks and other Blocks of that kind as proven in the video. Another difference is that moving blocks will be stored as tile entities instead of entities; this might make it possible to stand on moving pistons and blocks without falling through.

Bugs

 * If you try to push certain (mostly non-solid) blocks with a piston, your game will crash with the "Saving chunks..." screen, and the world will become corrupt. (Fixed in Beta 1.7_01)
 * In some cases the above happens, if a piston is use to block currently flowing water (crashing the game). A crash way of fixing this is to use MC edit to delete the blocks the piston and its extension are occupying.