How to Be a Good Programmer

With the Python tutor with the visualizations, you can imagine someone making a visualization. It's like an instructor using PowerPoint to very carefully draw out pointers and listening lists or data structures. But then what if as a student you're like, wait, I want to change this code to make it go backwards or something? And the cool thing about having a real tool that you can just change your own code and see the new visualization is wonderful.