The Khan Academy, known for their thousands of video lessons, has just rolled out a new interactive programming section. Work on the programs while, in real time, the effects of your changes take place in the sidebar.
It’s a great way to see the impact of your code the second you make changes. In the above image, we were working on a line-art drawing based on a simple bit of code; every time we changed so much as a single number or a parenthetical, the preview changes instantly. Hit up the link below to take a tour of the new interactive programming section.