Meanwhile, what were Jin and the others up to?
"I recently thought of something kind of interesting."
"Oh? What is it?"
"A beetle-type flight unit."
"Huh?"
"A... beetle?"
In truth, there were very few insects on the Pandor Continent. So even when he said "beetle," the concept didn't seem to click right away for Eira or Kachea.
"I see... It's something like this."
Jin quickly sketched something resembling a drone beetle or a female rhinoceros beetle on a sheet of scratch paper.
"Ah, that thing. I've seen one before....Uh, where was it again?"
"Eira-san, it was probably during our study trip to the Shouro Empire. Remember how one flew toward the window light at night?"
"That's it!"
Most insects possess what is known as phototaxis—a behavioral tendency to move while maintaining a constant angle relative to a light source.
Moving toward light is called positive phototaxis, while fleeing toward darkness is called negative phototaxis.
Insects that gather around lamps exhibit positive phototaxis.
Furthermore, rather than simply flying straight toward a light, they also tend to fly at a fixed angle relative to it. While this works fine when navigating by the sun or the moon, artificial streetlights can cause them to circle around endlessly, much like orbiting planets.
Digression aside.
"Anyway, these beetles fly like this."
Jin drew a sketch of a drone beetle opening its forewings and flapping its hindwings to take flight.
In reality, rhinoceros beetles (both male and female) fly by spreading their forewings into a V-shape, whereas drone beetles keep their forewings closed and fly using only their hindwings.
Be that as it may, Jin's point came across clearly enough.
"I see. So you're saying we should make an exterior shell that opens up into wings."
Jin nodded.
"Yeah. Though I looked into it a bit on my end, and it seems this method becomes less practical the larger the scale gets."
"Hmm? Why's that?"
"Well, you see..."
Jin considered how best to explain it.
This fell under the domain of fluid dynamics. To put it simply, the larger and heavier an object is, the less it is affected by the air, whereas the smaller and lighter it is, the more pronounced those effects become.
A small, lightweight model airplane will glide even when tossed by hand, but a large, heavy aircraft cannot generate enough lift to take off without powerful engines to build up speed.
"I think I get the gist of it."
"Ah, so that's why you're limiting this to small golems?"
Eira grasped the explanation in broad strokes, while Kachea understood why Jin had brought the idea to them in the first place.
"That's exactly it."
Even without relying on this method, Jin had other means of making golems fly, but he could hardly reveal those for the time being.
"Yeah, if we can pull that off, tucking the main wings away when they're grounded would look so sleek!"
When Jin had inspected their work earlier, they had been relying on an umbrella-style folding mechanism.
"Ah, what if we folded up thin, durable wings and unfolded them when taking flight?"
That concept was inspired by the beetle's hindwings.
"Yeah, as long as we can ensure sufficient structural strength, I think that's a great idea."
In Jin's estimation, the concept would probably work well for a golem around ten centimeters tall.
However, what Eira and the others were currently developing were forty-centimeter-class small golems.
For that scale, pairing smaller fixed wings with a powerful propulsion system was arguably the more practical choice.
Setting aside the beetle-type flight unit for the moment, the three of them turned to their original agenda: practical applications for three-dimensional magic circles.
"To recap: when using a magic circle instead of a magi-crystal, if we don't choose the application carefully, it becomes terribly clumsy to use or suffers from poor performance."
Eira nodded in agreement with Jin and chimed in.
"Right. So it's best suited for things that run continuously at low output, or devices where the output changes gradually."
Kachea joined in to summarize the point.
"Making them three-dimensional broadened our range of applications and made them much easier to control, but their underlying characteristics haven't changed."
"Considering those properties, what kind of practical uses can we come up with?"
This was the crux of the matter. Magi-craft was never meant to be mere academic theory; its purpose was to benefit people's daily lives.
That philosophy had been passed down continuously ever since the days of the First Generation Magi Craft Meister, Adriana Barbora Tsetse.
"How about magical lighting?"
Kachea was the first to offer a suggestion. Jin voiced his approval.
"Yeah, that's a good one. Mana consumption is low, and it basically only has two states: on and off."
"And then there's the water pump Kachea mentioned earlier. It needs a fair bit of power to lift water, but the workload is steady without sharp fluctuations."
Eira also threw her support behind Kachea's concept.
"That works too. And like I mentioned before, I think a water heater for bath facilities would be another great fit."
"Wouldn't ventilation systems for places like mines work well, too?"
"How about heating systems for smelting furnaces?"
"We could probably use them for refrigerators and freezers."
"It might not be the most practical, but we could make decorative fountains, couldn't we?"
"I think it'd be well-suited for clocks."
"Couldn't we adapt it for washing machines?"
"What about space heaters for regular households?"
"A doorbell might be nice."
"It might not hold up against heavy impacts, but couldn't we project a basic barrier?"
"Could we apply it to boring machinery?"
Idea after idea poured out in rapid succession.
Calc faithfully recorded every single suggestion in the meeting minutes.
"Wow, we came up with quite a list."
Kachea looked on in admiration, but Eira let out a sigh.
"Mmh, I'd love to try building all of them, but hardly any of this falls under Go-lab's jurisdiction."
She sounded a bit downcast.
At the academy, laboratories were organized strictly around specific research themes, and straying significantly outside one's assigned field was discouraged.
It was an essential rule for maintaining order across the institution.
"Hmm, isn't there some way around that?"
As one of the founders, Jin could hardly set a bad precedent by openly breaking the rules.
Just then, Reiko chimed in with a suggestion.
"Father, could you perhaps register this under a temporary research theme?"
"A temporary one, huh... That might just work."
They could frame it as a limited-time research initiative to develop and test applications for three-dimensional magic circles—active only while Jin was present.
If they demonstrated practical value during that period, the academy could formally consider establishing a dedicated new laboratory for the theme later on.
"All right, let's go with that."
"Please leave all the paperwork to me!"
Kachea declared with brimming enthusiasm.
Jin was just as eager to see this project reach a solid milestone, and he gave his full support.