Well I wouldn't necessarily say that they are looking for something specific. In the sens of looking for leadership. Or looking for a "rolling Stones" song.
The nature of this personal question (or curve-ball) is open-ended as far as content goes. Meaning there likely is no wrong answer. They are of course looking for CREATIVITY in how you deal with the content, in precision of thought, and breadth of imagination, as well as testing your writing skills. I would say equally important is that in terms of the rest of the essays think 1. How this fits into the big picture 2. How this ADDS something beyond what you have in the rest of your essays.
And that is a good place to start.
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