Graphics Reference
In-Depth Information
Most physical objects have an analog behavior. Analog systems are continu-
ous, meaning that they transition smoothly—like the minute hand of a clock
that moves smoothly through the ininite intermediate positions around the
hour. A digital clock, however, does not move continuously. It has exactly 60
intermediate states, and it lingers on one state and then switches to the next
instantaneously. Computer iles are digital, in that they are composed of ones
and zeroes. There's nothing in between.
In contrast, most current manufacturing techniques could be considered
analog since produced materials are practically continuous. But that doesn't
need to be the case.
I irst met Neil Gershenfeld at his MIT Center for Bits and Atoms. Frankly,
I was envious of the great name he chose for his center. I couldn't have come
up with something that captures the essence of my own work any better. It
was the summer of 2005 and we had just inished our irst round of battery
printing. The printed battery was “digital” only in the sense that it was elec-
tronically active, but it was physical and very analog in both other senses: It
was composed of continuous streams of raw material.
I described our circuit printing effort at length. Neil's response was impa-
tient. “Why not just deposit a chip with the whole prefabricated circuit in it?”
he asked, as he reached into a drawer and pulled out a tiny transistor-chip,
not larger than grain of rice. What if instead of droplets of ink, you deposited
droplets of . . . circuits?
At irst, I thought Gershenfeld missed the whole point. Dropping in prefab-
ricated circuit components is a cheat—it defeats the whole point of printing
circuits in the irst place. But the more I thought about it, the more it made
sense. Biological life is composed of 22 building blocks—amino acids—that
arrange themselves in different permutations to give rise to a myriad of pro-
teins and eventually life forms.
Biologists are quick to point out that there's much more to life than amino
acids. Of course, living things need energy to put amino acids together and
take them apart. But to a large extent, life's structure is composed of amino
acid building blocks. This makes it possible for biological life forms to repair
themselves. Animals and plants can consume each other and reuse the bio-
material because we are all made of the same relatively small set of just
22 building blocks.
