Scrimba: a video format for communicating code
Super cool.  One issue...I was watching the flexbox video and modified the CSS code but the view layout didn't update.  I clicked the save button thinking that would update the view, but then it had me sign up.  After signing up, I ended up with a fork of the video.  Cool, but not what I wanted.All I really wanted to do was fool around with the code while I had it paused, see the updates in the layout, and click play again - at which point I would have expected the code to revert to the script.