I've written plenty of code that uses arrays. Looped over them, indexed into them, passed them around. But if you stopped me and asked what an array actually is — not the syntax, not the API, the thing itself — I wouldn't have had a good answer. I knew how to use arrays. I didn't actually understand them. That bothered me enough to start digging, and the question didn't stay contained. It went through the runtime, through memory layout, through the hardware underneath, until it landed on transis