object-oriented programming

Inigo Quilez live-codes a painting using only mathematics in a shader, building it up step by step. The linked Shadertoy source shows the result.

James Trunk introduces Clojure syntax and thinking, covering its core data structures, immutability, the thread-last macro and live data analysis in the REPL.

Harry Schwartz gives a roughly hour-long tour of Emacs Org mode as an outliner, task manager, markup language and agenda tool. He demonstrates how he uses it for documents, presentations and todo lists.

Markus Triska tours Prolog's most distinctive features, including its use as a database and query language, rule processing, constraint solving and compile-time rewriting. It also covers concise meta-interpreters.

A screencast tutorial on Specter, a Clojure library for navigating and transforming nested data structures declaratively, demonstrated in a REPL.

Allieway Audio gives an informal introduction and live-coding demo of ORCA, a free esoteric programming environment for building procedural sequencers from Hundred Rabbits. It walks through the interface and how to make music with it.