Carpet

Carpets are thin blocks used for decoration. They are the same thickness as pressure plates. They are useful if you want a carpeted floor without using wool blocks as the material. They have a negligible hitbox, allowing a person to walk over them without elevating $1/16$ of a block. This is similar to how pressure plates work, although you cannot fall through a carpet. Carpets can be helpful when carpeting upstairs rooms without the ceiling of the next floor down being partially made of wool.

Usage

 * Carpets must be placed on a block, and cannot be placed freely or be free-floating in the world.
 * Carpets can be pushed and pulled by pistons/sticky pistons, but will pop off if pushed onto a hole.
 * You can craft Carpets in different colors by placing two blocks of wool of your desired color next to each other. This means that you do not need a crafting table to make them.
 * Carpets cannot be crafted with two differently colored wool blocks.
 * Carpets can break falling sand and gravel.
 * Carpets can be used as a safer alternative to decorative flooring, as wool is flammable, but interestingly, carpets are not.
 * Carpets are a more efficient alternative to flooring than full wool blocks.
 * Carpets do not prevent mobs from spawning.
 * Carpets placed above, or around, mushrooms growing naturally under trees will break the mushrooms if the mushroom is in a high light level, but will not break the carpet, leaving a floating carpet.
 * Carpets can be used to hide redstone wiring, pistons, hoppers, dispensers, and droppers.

Trivia

 * It is possible to use them to make a more realistic table by placing them on fence posts next to each other. However, you still can't put blocks on the table.
 * Carpets have a bottom texture.
 * Carpets can be destroyed by fluids.
 * Carpets are not flammable.
 * When you place blocks on it, those appear a block above the carpet -- like other partial blocks, carpets "claim" the entire block.
 * Unlike Pressure Plates, carpets cover the entire square they are placed on.
 * Carpet is opaque block, however, it does not decrease light going through it. Undead mobs like zombies burn underneath it in the daylight.
 * Carpet allows light to pass through it. Therefore, placing carpet on a pool of lava will allow you to walk across without losing light. (At the risk of being occasionally set afire!)  This also allows hiding  house lighting in the floor, rather than taking up wall, floor, or overhead space.  Hiding ugly jack-o-lanterns is especially helpful for making a space look nice.
 * If the player sprints across carpet, the particle effects are those of the blocks that are directly below it.
 * Orange & blue wool blocks gathered from desert temples sometimes will not work for carpet crafting in the initial 1.6 release.

Gallery
Teppich Tapis カーペット Dywan Ковёр 地毯