My understanding of the Duration : Ring and Target : Circle is that these parameters affect what is inside the traced circle.
Can a spell with D: Ring and T: Circle be casted on a previous spell to improve its durability?
For example, let's take circle Ward Against the Beasts of Legend (corebook, p. 120)
The spell is traced in dirt.
Then, the magus casts The Circle made of Stone, described below.
The Circle made of Stone
MuTe 10
This spell, when casted on a dirt circle, transforms it into stone, making it more resilient to damage, reducing the possibility of being broken.
(Base 3, Change dirt to stone, +1 Touch, +2 Ring)
Can Ring / Circle effect be casted to affect the ring from another spell? Or, are ring inside themselves?
Considering that a Ring of protection against demon/faerie/magical beast can either trap creature inside or prevent them from going inside, one can assume that the circle cannot be reached by said creature whether inside or outside, thus I (personal interpretation) would be tempted to conclude that the circle itself contains himself since creature cannot interact directly with it.
So, if a spell would turn a chalk-drew circle into a more robust stone one, with a duration of ring, it would be permanent until broken, where two things will happen simultaneously: the broken stone circle will revert to a broken chalk circle and the initial spell maintain by the chalk circle would also stop.
You can decide if a Vim requisit would make sense since the Circle made of Stone is not just cast on a simple circle, but a magical circle.
To nitpick, one can see two cases:
Drawing a chalk circle, turning it into stone (no requisit required since it is just a chalk circle), then cast the spell on the stone circle (with the mage tracing the stone circle with his finger or any appropriate way). It takes at least three rounds: one to draw the chalk circle, one to cast the spell turning the chalk into stone (possibly more than a round depending on its size), then finally casting the main ring-duration spell (for at least a round or more depening on its size).
Drawing a chalk circle while casting the main ring-duration spell (casting time depending on its size), then turning the chalk circle into stone (here again, casting time depending on the size of the circle). This second spell might or not require a Vim requisit, depending on your interpretation. The advantage of this second method it to grant benefit of the circle effect earlier, while turning it into stone.
While I'm looking forward to the definitive edition, we can't hold our breaths till it comes out.
6 Months before the project is posted. Add another 6 for the campaign & production/shipping... A year is a long time to not know if a circle used as a ring/circle can be targeted and that the duration benefit from Ring also.
Side note... almost 1500 people waiting for the definitive Ed.
I keep thinking of a Summoning circle.
If the boundary circle is within its effect, then the summoned creature can reach the circle and break the circle.
That seems inconsistent with tales how Summoning circles work.
