three layer circle

"So," Kim said, finally. "What can you tell me about that?" She gestured toward the piece of paper with her fork.
I swallowed my food, took a sip of the rich ale, and picked up the paper again. "All right. This is a figure of High magic. Three of them, really, one inside the other, like layered walls. Remember what I told you about magical circles?"
Kim nodded. "They either hold something out or keep it in. Most work on magic energies or creatures of the Nevernever, but mortal creatures can cross the circles and break them."
"Right," I said. "That's what this outermost circle of symbols is. It's a barrier against creatures of spirit and magical forces. These symbols here, here, here, are the key ones." I pointed out the squiggles in question.
Kim nodded eagerly. "I got the outer one. What's the next?"
"The second circle is more of a spell barrier to mortal flesh. It wouldn't work if all you used was a ring of symbols. You'd need something else, stones or gems or something, spaced between the drawings." I took another bite of steak.
Kim frowned at the paper, and then at me. "And then what would that do?"
"Invisible wall," I told her. "Like bricks. Spirits, magic, could go right through it, but mortal flesh couldn't. Neither could a thrown rock, bullets, anything purely physical."
"I see," she said, excited. "Sort of a force field."
I nodded. "Something like that."
Her cheeks glowed with excitement, and her eyes shone. "I knew it. And what's this last one?"
I squinted at the innermost ring of symbols, frowning. "A mistake."
"What do you mean?"
"I mean that it's just gobbledygook. It doesn't mean anything useful. Are you sure you copied this correctly?"
Kim's mouth twisted into a frown. "I'm sure, I'm sure. I was careful."
I studied her face for a moment. "If I read the symbols correctly, it's a third wall. Built to withhold creatures of flesh and spirit. Neither mortal nor spirit but somewhere in between."
She frowned. "What kind of creatures are like that?"
I shrugged. "None," I said, and officially, it was true. The White Council of wizards did not allow the discussion of demons that could be called to earth, beings of spirit that could gather flesh to themselves. Usually, a spirit-circle was enough to stop all but the most powerful demons or Elder Things of the outer reaches of the Nevernever. But this third circle was built to stop things that could transcend those kinds of boundaries. It was a cage for demonic demigods and archangels.
Kim wasn't buying my answer. "I don't see why anyone would make a circle like this to contain nothing, Harry."
I shrugged. "People don't always do reasonable, sensible things. They're like that."
She rolled her eyes at me. "Come on, Harry. I'm not a baby. You don't have to shelter me."
"And you," I told her, "don't need to know what kind of thing that third circle was built to contain. You don't want to know. Trust me."
She glowered at me for a long moment, then sipped at her ale and shrugged. "All right. Circles have to be empowered, right? You have to know how to switch them on, like lights?"
"Something like that. Sure."
"How would a person turn this one on?"
I stared at her for a long time.
"Harry?" she asked.
"You don't need to know that, either. Not for an academic interest. I don't know what you've got in mind, Kim, but leave it alone. Forget it. Walk away, before you get hurt."
"Harry, I am not - "
"Save it," I told her. "You're sitting on a tiger cage, Kim." I thumped a finger on the paper for emphasis. "And you wouldn't need it if you weren't planning on trying to stick a tiger in there."
Her eyes glittered, and she lifted her chin. "You don't think I'm strong enough."
"Your strength's got nothing to do with it," I said. "You don't have the training. You don't have the knowledge. I wouldn't expect a kid in grade school to be able to sit down and figure out college calculus. And I don't expect it of you, either." I leaned forward. "You don't know enough yet to be toying with this sort of thing, Kim. And even if you did, even if you did manage to become a full-fledged wizard, I'd still tell you not to do it. You mess this up and you could get a lot of people hurt."
"If I was planning to do that, it's my business, Harry." Her eyes were bright with anger. "You don't have the right to choose for me."
"No," I told her. "I've got the responsibility to help you make the right choice." I curled the paper in my fingers and crushed it, then tossed it aside, to the floor. She stabbed her fork into a cut of steak, a sharp, vicious gesture. "Look, Kim," I said. "Give it some time. When you're older, when you've had more experience ..."
"You aren't so much older than me," Kim said.
I shifted uncomfortably in my seat. "I've had a lot of training. And I started young." My own ability with magic, far in excess of my years and education, wasn't a subject I wanted to explore. So I tried to shift the direction of the conversation. "How is this fall's fundraiser going?"

Fool Moon Chapter 1, Page 3-8


"He's right," MacFinn said quietly. "We split up. The first one discovered makes a lot of noise, puts up a fight, and gives the others a chance to get away."
"No," I said. "MacFinn, you've got to stay with me. I can make the circle with some sticks and dirt, if necessary, but if I'm not there, I can't hold you in when the curse takes hold later tonight."
MacFinn's teeth showed again. "No time to argue, Mr. Dresden," he said.

Fool Moon Chapter 15, Page 171-173


I just had to pray that I would be able to get the circle up around MacFinn before I had to find out. I checked the bucket, to make sure I still had the chalk and the stones I would need to construct the greater circle around MacFinn. You didn't necessarily have to make them out of silver and gold and whatnot. Mostly, you just had to understand how the construct channeled the forces that were being employed. If you knew that, you could figure out how to make it out of less pure materials. The very best wizards don't need much more than chalk, table salt, and a wooden spoon to pull off some remarkable stuff.

Fool Moon Chapter 17, Page 190