Knotter is a highly configurable interlace designer. Interlace patterns are a kind of design historically used as a decorations in many places and by different cultures (some examples are Celtic knotworks and Islamic interlaces). Knotter aims to allow its user to design such patterns in an intuitive way and to provide easy ways to integrate the result into external general-purpose graphic software. For this purpose, designs created within Knotter can be saved in a custom human-readable format and exported as Scalable Vector Graphics and in a wide number of raster image formats.
Qtnp is program for math\physics teachers and students. There 4 tools: Pen, Line, Jogged line, and Circle. The software can draw grids, coordinate planes, and graphics. It has flexible settings, presentation mode, support for all base formats, a GUI for blackboards/tablets, and a built-in powerful calculator.