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 no collision detection, allowing a person to walk over them without elevating 1/16th of a block. This is similar to how thin snow and pressure plates work. Carpets used to be a very inefficient building material, because crafting one carpet tile would consume two blocks of wool. As of snapshot 13w17a, you produce 3 pieces of carpet per 2 wool blocks. 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 solid blocks, 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 non-solid block, or over a hole.

You can craft them 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 an safer alternative to decorative flooring, as wool is flammable, but carpets are not.

When you use carpet to decorate the floor instead of wool blocks, it wont change the way the ceiling looks in the room below it.

History
Teppich Tapis カーペット Ковёр 地毯