it’s potato’s four elements! But I don’t know what it means.

@RedTriangle  
Doesn’t need an incantation. Vast majority of Arcane circles and magic has no incantation.  
Still Starlight was pushed in and all of it started meaning she was being used as a living battery.

Is there an alt to the SVG because it just won’t load for me at all.

@RedTriangle  
well cozy did trick starlight into the circle so maybe that’s what activated it

@neo4812  
I remember Fullmetal Alchemist.
 
Still, it’s more than drawing a magic circle, it needs energy and incantation to activate.

@RedTriangle  
How do unicorns use magic? The answer, probably these runes on the interior of the horn.

@RedTriangle  
maybe its like alkahestry from FMA:B

Wait a second, how does Cozy Glow, who is not a Unicorn, can use magic?

By the way, impossible to do a frequency analysis on the amount of text in the show

bout time someone made a kinda clean version of this circle! getting some strong FMA vibes here

@ThePonyTheorist  
Yea, they move, but now that I’m thinking about it, maybe there’s one “canon” arrangement present, the most common one. Just like how ‘black right hand’ in animated media can be left hand in some rare shots.  
@ThePonyTheorist

I noticed that top and bottom semicircles are bigger than other semicircles. Also, Tirek’s horns are the only pic that actually touch outer circle and crescent.

You can easily check for it - next to each ‘M’ / ‘3’ there should be either the Helm of Yickslur or Knuckerbocker’s shell.

Also, are you sure the artifacts move around? I thought that temporarily, but when I took a second look, it seemed more like the camera was moving position.

Keep note that SOMETHING also needs to be coding for the magic to actually be dragged into the portal instead of just bursting out again - that may actually be a more fair translation of the runes to the left and right. One ‘world’ with a piece missing, one ‘world’ with a piece added…

@Background Pony #C9A9  
Yes.
 
The ‘cresent moons’ are probably just focusing the power of the artifacts, though there may be some significance due the semicircles around them. I haven’t thought of anything for that…
 
Now, as for the central area; Just look at the crystal empire. the 6-pointed star is synonymous with drawing in magic/emotions to a central point, therefore that same point is at play here. Tirek’s horns are obviously aiding in the suction somehow.
 
I never noticed it before, but good eye with thinking the bottom part is a wing! I’m unsure, and this is VERY nebulous, but perhaps that’s how it levetates the ball above itself. That, or it’s a clause stating “specifically do NOT drain Pegasus magic”, hence allowing Cozy to keep her own.
 
The parts to the sides? I got nothing. Related to the hands? Maybe, but that could easily be coded in the text.

@ThePonyTheorist  
Very nice 👌.
 
By unconnected you mean ring-shape at the center, inside starburst?

You have all of them, though in the last ‘segment;, I missed the V, and had the “LOI” as “IOI” - Still very similar.
 
You’re missing something out on your ‘basic shape’, I think: Note the inner circle which is unconnected to the other one. Never have I seen THAT in a rune before (especially both of Starlight’s, which is the closest to the meaning of the one we see here), which may indicate some importance in how it sucks in magic, holds it, or actually keeps a stable portal.
 
Nevertheless, I think we can make some inferences. A 3-sided triangle allows what seems to be 2-dimensional travel of an object through time. A 5-sided pentagon allows 4-dimensional travel of Twilight and Starlight through both time and space. I suspect that the outer 6-sided hexagon in this rune is what’s calling for 5-dimensional extradimensional travel. From this inference, i’d also hypothesise that a square would call for 3-dimensional teleportation.

Noticed that some ‘letters’ are missing in some shots, while present in others. Corrected version:  
 
Tell me if you noticed some screencaps with additional ‘letters’ that are missing here.

@Background Pony Number 17  
The latter. Definitely.

The animators are big on magic circles in this show. I don’t know if there’s any deeper meaning to it, or if “circle with geometric shapes and weird sort-of-letters around the edge” is their standard shorthand for “this is magic”.

@Background Pony #C9A9  

 
The central ring is the “containment sphere” that holds Starlight, all the magic & the young six.  
The “Horns” on the top the active “Draining Arcana Magic” component (likely inspired on Tirek´s horns).  
The “9 i” on the sides is the “hands” that grabbed the CMC & the young six (a reactive trap).  
The “wings” on the bottom is the “Plane Transfer” final trigger that sends stuff to another world.

Top part look kinda like Tirek’s horns, bottom part looks kinda like wings. Though it’s not likely wings, why would there be wings?