Claytronics is an abstract future concept that combines nanoscale robotics and computer science to create individual nanometer-scale computers called claytronic atoms, or catoms, which can interact with each other to form tangible 3-D objects that a user can interact with. This idea is more broadly referred to as programmable matter. Claytronics has the potential to greatly affect many areas of daily life, such as telecommunication, human-computer interfaces, and entertainment.
So, claytronics can be programmed by computer. For example:
There is a thing shaped cube but a person want to change its shape to round / ball, only by touch it, the thing can change its shape, ti's called Claytronics.
Here's a fun video about claytronics, it's very awesome and it's in development.