As I see it, the number one hurdle in software productivity is human understanding. The more understandable software is and the easier it is to make software understandable, the faster and more accurately it can be modified.

This is why functional models like React, DSL models like SQL, and constraint models are so widely used — they make what's happening in the software more understandable (at a worthwhile performance cost).

A few of my own contributions:

* Legible Mathematics: http://glench.com/LegibleMathematics/

* Flowsheets – showing data as you program: https://www.youtube.com/watch?v=y1Ca5czOY7Q

* REPLugger – showing data as you program in large systems: https://www.youtube.com/watch?v=F8p5bj01UWk

* FuzzySet interactive code documentation: http://glench.github.io/fuzzyset.js/ui/