I don't understand or appreciate what the mystique of creativity is. The inside of the black box could just be your brain randomly remixing concepts and evaluating the variations. Most of them are probably nonsensical (“purple monkey dishwasher”) but some of them are interesting (“monkey dishwashers”) and then you take that idea and keep mixing it. The ideas that gets mixed are just whatever you’re able to pull into context, so ideas you’re familiar with are more likely to get mixed. Sometimes you struggle to come up with creative ideas, and it’s because you’ve run out of new ideas to mix with so changing your environment helps by injecting new ideas.

But at its core creativity is, at a practical level, just remixing ideas and applying some value metric against them.

Regarding the article, you can apply creative remixing at multiple levels so a creative nonfiction writer may start with fixed facts but can still remix the order, presentation, format, where to begin/end, etc.