A hypothetical machine to operate at nanoscale [img:d1b3e4e51c]http://mw.concord.org/modeler1.3/mirror/nano/gear4.gif[/img:d1b3e4e51c] [img:d1b3e4e51c]http://mw.concord.org/modeler1.3/mirror/nano/gear4a.gif[/img:d1b3e4e51c] [url]http://mw.concord.org/modeler1.3/mirror/nano/gear4.html[/url]