Block entity

Tile entities are additional data for a block, beyond the block ID and 4 bits of so-called metadata that every block has (as described in the data values article). In addition, tile entities are able to perform an action each tick.

The blocks which have tile entities are:
 * Signs, to store the text to be displayed.
 * Chests, Dispensers, and Furnaces, to store their contents. Furnaces also store the time until the current item is smelted, and the time until the furnace's current fuel item is exhausted.
 * Monster Spawners, to store which mob will be spawned and the time until the next mob is spawned.
 * Note Blocks, to store which note will be played.
 * Blocks being moved by pistons, to store the offset of block, direction of movement, and ID of moving block.
 * Jukeboxes, if and which music disc is inside
 * Enchantment Tables for the floating book.
 * Brewing Stands to store the items and brewing time.
 * End Portals for whether an eye of ender is in or not.