"Do six little angels learn faster than one?"

"Well," says Isabella, "they'd have to learn the same things, like how to walk and talk and use their hands and flap their wings, but if you count all of it separately, then yes, about six times as fast."

Isabella laughs. "Well, first of all, that would be very uncomfortable. You saw how big I got when I was pregnant with just Keziah; imagine if there were six of her! And second of all, that's not what I meant. Imagine you're drawing with chalk, a line on the floor from that wall to this one. If you draw six lines at once, with six pieces of chalk, then there will be six times as much chalk on the floor, but the lines will still only go from one wall to the other."

"But then that's not any faster at all!" says Damaris.

"More learning happens, in the same amount of time," says Isabella. "That's a kind of faster. The kind of faster you want is the same amount of learning in less time."

"The same in less time is what faster means," Damaris insists.

"Well, I suppose it all depends on how much you're trying to get done."

"What's that mean?"

"Well, let's suppose it takes three years for a little angel to become interesting," Isabella says, rocking a sleepy Keziah in her arms. "And let's say I'm only going to have two, that Keziah's going to be the last one. So when she's three, she'll be interesting, and if she could be interesting when she's two instead, then all my little-angel-interestingness would be done faster. But what if I'm going to have six of them? Then by the time the last one was interesting, you would be at least ten years old, if I had them one at a time. If they all were born at the same time then the same amount of little-angel-interestingness would be done faster, even if it still took them all three years."

"I'm not sure how many little angels we're going to have, but being done faster is not the point," says Isabella, amused.

"Why not?"

"If you sing a song twice as fast, you'll be done sooner. Why do we sing some songs slow anyway?"

"They sound nicer?" she guesses. "Do one-at-a-time babies sound nicer than twins?"

Isabella laughs. "No. All right - why do we sing at all?"

"Because it's fun!"

"And bringing up little angels," says Isabella, rocking sleepy Keziah and re-folding a limp wing, "is also fun."

"Even the boring part?"

"I wouldn't want to miss it."

"Okay," says Damaris, dubiously.

"Right now you are three," says Isabella. "Would you want to be magicked into being six instead, right now? And miss being four and five in between?"

"I don't know," says Damaris. "I've never been four yet!"

"Keziah hasn't been one year old yet," says Isabella. "I don't think it would be fair if she never got to try it, even if that would make her interesting faster."

"Oh," says Damaris.