"I would not have expected that. Interesting."

"How much farther have we to go?"

"Only one more night after this. That's when we've been travelling, since it's cooler. We woke up about an hour ago."

"I see. You had more exercises?"

"Ah, yes. These ones are for drawing circles." Occlus is handed a stick with horsehair on one end, a pot of ink, and a sheaf of paper. "I've written some designs that don't correspond to actual arrays but use similar geometric elements. You are to reproduce them exactly."

"I see."

"The next exercise is to do it in soft sand or ground. If you're curious."

Then precision and accuracy with a range of materials is of importance. She practices, but not having had previous cause to master the art of freehanding a perfect circle, does not achieve an exact copy before they start moving for the night. And a moving wagon is a less than ideal workstation.

It's a pity she's not more practiced at it, drawing circles while moving is a skill in itself.

In the meantime Hohenheim and Lin can teach Occlus Xingese, unless she wants to meditate some more.

Learning the language is an adequate use of her time.

It goes along quickly, thanks to that device of hers. "Do you still object to explaining how it works?"

"We have more time, now. How detailed an explanation do you wish?"

"That depends on whether I could theoretically reproduce it."

"Perhaps not exactly, but there is a proof that you can construct something functionally equivalent. Fundamentally, this device is an exceedingly efficient calculator. The translation works because it knows an algorithm which defines the process of learning a language in mathematical terms."

"I'm not sure what you mean by calculator."

"Calculator, that which calculates, or performs mathematical operations."

"I believe that Amestris has mechanical adding machines that do arithmetic operations? I've known people who have, when asked about their profession, described themselves as calculators."

"The principle is the same. This is more precisely an electronic calculator, because it stores numbers as electric charge."

"Ah. ... you might find it helpful to broadly assume I don't know about electronics more advanced than radio."

"The precise details of implementation are negotiable, the logic behind the design is more important." And she can give an impromptu lecture on the basics of circuit design.

Unsurprisingly, Hohenheim listens well. He's attentive, interested and has an excellent memory.

An intelligent student is her favorite sort. This is not her primary area of expertise, however, and her lecture doesn't stretch more than a few hours.

When she's finished Hohenheim sits for a minute and processes. He could spend time learning to make one of those devices now. But it's still not going to be as effective when battling Homunculus as talking to his souls, since otherwise they could be stolen from him and increase Homunculus's power.

Perhaps he should start thinking of strategies that don't assume he'll be the main combatant. If he has Occlus to help him kill Homunculus he could spend his energy elsewhere.

... or perhaps he should listen to his hunch that Occlus needs more persuading and isn't entirely won over, even with his promise to teach her alchemy.

"We're almost at the city. Normally I use my skills to heal or do repairs. I can show you some real arrays that fail gracefully if you make a mistake."

"I would be amenable to that."

Occlus learns how to fold paper with alchemy!