Just as I want my microwave to heat many different kinds of food, and my home computer to run lots of different programs, I’m hoping my desktop nanofactory will produce a wide variety of products. One thing in the nanofactory video that’s rarely mentioned but I think fairly prescient is that there is a nice balance between fast inflexible assembly lines in the early assembly stages and robot arms later on, where it makes sense, having built little blocks with different little functions, to connect the blocks together in different configurations. (Chris Phoenix’s paper from a few years ago, discussing nanoblocks, is also prescient in this regard.)

Potentially useful mental models here are programmable logic chips such as FPGAs, which offer a huge amount of flexibility in a standardized package, and the software engineering practice of profiling, which is the measurement of code execution time on a function-by-function basis, and which is the only reliable way to decide which code is worth the trouble to hand-optimize. There is probably an assembly line equivalent of software profiling, just as Chris’s nanoblocks can be thought of as nanomechanical equivalents of FPGAs. (At least that’s how I think of them.)