Just to add to this discussion, some quasi-related links with regard to visual presentation of code:

• Experiments in Code Typography (McDirmid, Microsoft) http://research.microsoft.com/en-us/projects/liveprogramming...

• Typography of Code (MAX 2010): https://youtu.be/mG0lyGekGDs (alternate recording: https://youtu.be/r2JePjrDggE)

• Elastic tabstops: http://nickgravgaard.com/elastic-tabstops/

Of course, there's also numerous projects with more significant visual representation, like Blockly, Scratch, flow programming, etc. And, of course, real-time feedback/simulation is another arena of usefulness e.g, http://research.microsoft.com/en-us/people/smcdirm/managedti..., Bret Victor's works, etc. But, I digress.