In the talk about data structures, I was reminded of Fred Brooks quote from MMM: "Show me your flowcharts, and conceal your table, and I shall continue to be mystified; show me your tables and and I won't usually need your flowchart; it'll be obvious." Several people have translated it to something like "Show me your code and conceal your data structures, and I shall continue to be mystified. Show me your data structures, and I won't usually need your code; it'll be obvious," for a modern audience.
Several years ago I was happy to work with several people with an interest in philosophical history. We whiled away the hours thinking about whether these quotes represented something of the tension between Hericlitus (You cannot step into the same river twice) and Plato (everything is form and substance.) So... I think the observation about the alternating utility of form and function is an old one.