(via) this is amazing Self replication project carried out at Cornell University by Viktor Zykov, Efstathios Mytilinaios, Bryant Adams, Hod Lipson.
Self-replication is a fundamental property of many interesting physical, formal and biological systems, such as crystals, waves, automata, and especially forms of natural and artificial life. Despite its importance to many phenomena, self-replication has not been consistently defined or quantified in a rigorous, universal way, nor has it been demonstrated systematically in physical artificial systems. Our research focuses both on a new information-theoretic understanding of self-replication phenomena, and the design and implementation of scalable physical robotic systems where various forms of artificial self replication can occur. Our goal is twofold: To understand principles of self-replication in nature, and to explore the use of these principles to design more robust, self-sustaining and adaptive machines.
The website provides an example:
Self-reproduction of a physical, three-dimensional 4-module robot: (a) A basic module and an illustration of its internal actuation mechanism; (b) Three snapshots from the first 10 seconds showing how a 4-module robot transforms as its modules swivel simultaneously. (c) A sequence of frames showing the self reproduction process that spans about 2.5 minutes. The entire reproduction process runs continuously without human intervention, except for replenishing building blocks at the two 'feeding' locations circled in red.
The video is stunning. Lots of precisions can be found in the faq.
A good read about this: Zykov V., Mytilinaios E., Adams B., Lipson H. (2005) "Self-reproducing machines", Nature Vol. 435 No. 7038, pp. 163-164
Why do I blog this? during my undergraduate studies I often encountered the very idea of self-replication, this is a very concrete example of how it can be embedded into real artifacts.