"Piece Of code" is too imprecise. A single instruction on a microprocessor? A subroutine? As another comment implied, does DNA count as code? Or transistor logi

"Piece Of code" is too imprecise. A single instruction on a microprocessor? A subroutine? As another comment implied, does DNA count as code? Or transistor logic within a microprocessor? A related but more subjective question I used to ask developer friends was "what's the most IMPORTANT piece of code written that can fit on one screen?". The best answer I got was rc4, written by an anonymous author but what made security, privacy, and digital commerce possible on the web.