time

A roughly 45-minute vintage US military instructional film that gives a comprehensive overview of celestial navigation, covering sextant use and the theory behind lines of position.

Inigo Quilez live-paints a mountain landscape using only math in a shader, building up from a basic polynomial noise surface through fractal terrain, lighting and atmosphere. The code runs in real time on Shadertoy so viewers can edit it as they follow along.

Inigo Quilez live-codes a cartoon character painting entirely from math, using signed distance fields in a Shadertoy shader. He explains each step of building the image from formulas.

A reupload of Joel Spolsky's talk teaching spreadsheet users the Excel features they are probably missing, such as keyboard navigation, named ranges, tables and lookups. The original disappeared and this copy comes from the Wayback Machine.

The first lesson of MangoJelly's FreeCAD 0.20 beginner course, covering setup, preferences and navigation. The series teaches fundamentals through complete workflows such as sketching, Part Design and STL export.

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.

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.

Tech Ingredients shows how to build a liquid panel with a specialty paint that, placed outside, cools below ambient air temperature. It demonstrates radiative sky cooling.