Concentric objects

I actually think the most helpful part of this episode was your breakdown of the, of, um-

Concentric circles

... yeah, concentric circles.

Can I ask you what, I was, I meant to ask you this when you, you, so you go Little "c" catholic in the center, right?

Some marks faded, but the pattern leapt out.

Concentric stone circles laid out exactly where we discovered them last night.

That's blood tide work, Callum said, voice gone thin.

Olden anything still standing.

Right.

Concentricity is what it's called, but-

Yeah

... that's what's super important.

This is where you take round parts and put them in a machine between centers and you hold.

Concentricity, which is what, when the parts are running in a turbine engine, you want them to be perfectly concentric.

So they don't bounce.

and he had a way of doing this in the 50s and the 60s of uh taking turbine shafts and grinding them to ultra precision which was it which is still point zero zero zero two um is our tolerance so your hair in your head is point zero zero three so if you take that and slice it ten times you take one or two of those and that's how much we're holding all day long and all of this

It was too deliberate, too geometrical.

Concentric rhombi, angular spirals, sometimes interlocking trapezoids drawn with unsettling precision, sometimes just a partial angle, like someone had run out of nerve halfway through.

I paused outside the observation suite, watching a technician polish a pane with circular movements, stopping only to stare into the reflection as if watching someone approach behind her own eyes.

When I arrived, she startled and then blinked away recognition, introducing herself twice.