OpenVSP (short for Open Vehicle Sketch Pad) is a free and open-source parametric aircraft geometry tool that helps users create and analyze 3D models of aircraft. It was originally developed with the support of NASA, which adds a layer of reliability and authenticity to the software, and released as an open-source project in 2012.

Mixxx is a free, open-source yet powerful DJ software solution for Windows, Mac and Linux platforms. It provides a comprehensive platform for both amateur and professional DJs, and offers a wide array of features that facilitate live mixing, including support for various audio formats, advanced beat detection, and a customizable interface.

In the Android ecosystem, facing the increasing size and complexity of applications, Google Play sometimes adopts a new format when distributing programs - Android App Bundle (with extension name .apks, AKA: split APKs), which enables developers to create multiple APK files that are optimized for different device configurations, such as screen sizes, CPU architectures, and languages. Unlike traditional APK file, which is a standalone package, split APKs are packaged together to create a more efficient distribution mechanism.

K-3D is a free and open-source 3D modeling, animation, and rendering system for Windows and Mac platforms. It integrates adaptable plugins with a visualization pipeline architecture, transforming K-3D into a robust and flexible tool for artists.

Using V2Ray to break through network blockade and access the Internet is undoubtedly the best choice at present. On the Windows platform, we have many choices, such as v2rayN and Clash; on the Mac platform, we can use ClashX, etc. But for Linux systems, we have even fewer choices. Fortunately, a very useful and highly extensible V2Ray GUI frontend on Linux is Qv2ray.