macos
Nebo is a free open-source software for note-taking that offers a dozen of productivity-oriented features. It supports handwritten notes, sketches, diagrams and exports your notes in many formats. Nebo is designed for touch screens, but it also designed to work with stylus and to write or sketch notes. One of
macos
Dia is a free open-source program for designing and building technical diagrams. It is fairly easy to use and can be installed on macOS, Windows, and Linux. Requirements for macOS The following requirements have to be met in order to use the DMG above: * Mac OS X 10.8 Mountain
web development
ASCIIFlow is a client-side only web based application for drawing ASCII diagrams. You can use it at asciiflow.com. Features * Extremely easy to use * Limited or no setup * Rich tools * Download and export your diagrams in multiple formats * Supports boxes, arrows, line, and text * Use your own version at your