As I and many others have stated before the key to good software engineering (and thus great software) is an understanding and use of the core, formal theories of computer science - I consider software engineering to be a sub-discipline of computer science (and in turn mathematics). Why should this be so? Simply because of understanding how each of the parts of a piece of software interact and an appreciation of the complexity and need for elegance and simplicity in this.
So what has this got to do with ballet? Comparing modern dance with ballet and the dancers performing their routines I noticed the approach to the task was in most cases different - there is an interesting exception which I'll get to later. The difference was in the execution, fluidity and attitude to the performance: how accurate the moves were being performed individually and collectively as a group. An interesting point I thought was that you could recognise the really talented dancers by how they looked at each other and the audience.
Modern dance seems to be (or is) very free in terms of movement, style and composition - akin to agile methods in software engineering. In some ways, modern dance is easy ... anyone can just move, similarly to agile methods, anyone can hack a project together. But to get a consistent, fluid, elegant whole is extremely difficult in that the choreography of the individual dancers becomes very difficult to make consistent, unless the dancers are very experienced and instinctively understand how each is moving relative to oneself. I suspect the very good dancers here have or understand the fundamentals of movement to a very precise degree.
Ballet on the other hand is very strict with a limited set of movements which themselves are precisely defined. Wikipedia's (sorry, I know you shouldn't cite wikipedia!) article on ballet contains the statement:
"It is a poised style of dance that incorporates the foundational techniques for many other dance forms."I need say no more regarding the basis of ballet for other forms of dance.
An in that respect we have our link with mathematics, computer science and software engineering. Formal methods are computer science's version of ballet: strict rules and technique and hard to master but forming the basis for the rest of the subject, especially software engineering.
When auditing, watching or even performing the "art" of software engineering - or at least - developing software (and systems); those who have an understanding (either explicitly or implicitly) a deep understanding of how the science works build the best software. The "moves" of the software engineer are deliberate, planned and executed with precision. This remains the same whether this is agile or formal development, though most agile development tends to be very ad hoc, messy, immature and poorly executed - like the modern dancer without discipline.
And indeed this is the core of what makes a good engineer - not whether they have the formal grounding, but they have an understanding of what makes the engineering work and the discipline to actually use those techniques properly.