  Molecular machines may resolve three distinct bottlenecks of scientific
advancement. Nanofactories (Phoenix, 2003) composed of MM may produce
atomically perfect products spending negligible amount of energy (Hess, 2004)
thus alleviating the energy crisis. Computers made by MM operating thousands of
bits at a time may match biological processors mimicking creativity and
intelligence (Hall, 2007), thus far considered as the prerogative of nature.
State-of-the-art brain surgeries are not yet fatal-less, MMs guided by a
nano-brain may execute perfect bloodless surgery (Freitas, 2005). Even though
all three bottlenecks converge to a single necessity of nano-brain, futurists
and molecular engineers have remained silent on this issue. Our recent
invention of 16 bit parallel processor is a first step in this direction
(Bandyopadhyay, 2008). However, the device operates inside ultra-high vacuum
chamber. For practical application, one needs to design a 3 D standalone
architecture. Here, we identify the minimum nano-brain functions for practical
applications and try to increase the size from 2 nm to 20 micro-m.
