encoding

Tom Stuart's Ruby Manor 3 talk builds FizzBuzz using nothing but Ruby lambdas, working through Church encodings of numbers, booleans and data structures. It is a hands-on introduction to lambda calculus.

Ned Batchelder's PyCon 2012 talk gives a quick overview of what Unicode is, then focuses on what a Python programmer needs to handle text correctly. It presents the 'Unicode sandwich' strategy: decode bytes at input, work with Unicode internally, encode at output.

A DEF CON 29 talk by Richard Henderson about encoding the EICAR antivirus test string into QR codes and barcodes and scanning them at real systems. Many systems that do not expect such input misbehave or collapse, including a parking garage system.