Very nice on all fronts: design, usability, and content. Source is here: https://github.com/danielkunin/Seeing-Theory https://github.com/danielkunin/Seeing-Theo

Very nice on all fronts: design, usability, and content. Source is here: https://github.com/danielkunin/Seeing-Theory https://github.com/danielkunin/Seeing-Theory (Apache licensed) Seeing projects like these makes me optimistic about EdTech. Such "math toys" and visualizations can really make otherwise dry STEM subjects come to life. See also http://immersivemath.com/ila/index.html http://immersivemath.com/ila/index.html which is linear algebra book with very good visualizations.