It seems to me that one of the real weaknesses of most introductory material in Computer Science is that it trivializes content: Examples are reduced to mere placeholders.
Learning to program is hard, but it becomes more accessible, I think, if the content of our examples draws from the worlds we already know. This is especially important for young scholars: The content of our examples should draw from their areas of expertise and familiar datasets that they care about.
These visualizations, for example, represent different ways of visualizing (simultaneously) all the data from a video stream. Student familiarity with (and passion for) the content of those streams makes learning easier and more intuitive, and it guarantees they will care about the output.