This document discusses claytronics, which is a concept that combines nanoscale robotics and computer science to create individual nanometre-scale computers called catoms that can interact to form 3D objects. Catoms are envisioned as self-contained units that can move and adhere to form shapes under software control. The document outlines the challenges of scaling catoms down while maintaining functionality. It also describes the software needed to program large ensembles of catoms through languages like MELD and LDP. Ultimately, claytronics could be used to remotely interact with physical 3D representations of objects and environments through a new communication medium called pario.