reference counting

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.

Mitchell Hashimoto walks through his setup for running a NixOS virtual machine on a Mac as his development environment, with a config repo on GitHub.

Tech Ingredients builds a pair of large Voigt speakers and explains ported, transmission line and horn designs. It tests them in an anechoic chamber and uses constrained layer damping for the enclosure.

The UK DVSA's one-minute guide to the hazard perception part of the driving theory test, covering when to click and how to score well.