Derrl opened his eyes. They were bright with curiosity. He looked over to the elder mage, his questions were visible on his face.
"What do you need to know?" He said almost irritably.
"Why were there some that were shifting, others that weren't, and many that just weren't at all there?" His questions were honest and important, to him at least.
"Those that shift do so because of their constant interplay with the world. Those are the runes that are always at work to accomplish what you told them to do. If you look at the rune on your temple, you would see that it shifts. It is not simply an impenetrable barrier. If it were simply that, you would not be able to move your jaw, the skin would not be elastic any more. So, as you shift, even minutely, the energies must re-adjust themselves. Even if they are only adjusting to a slight breeze, they still shift." He held his head with his lined hands, let them fall and continued his explanation. "As for those that are still, they are simple runes that need not be affected by their surroundings. They are often runes that would enchant a weapon, an arrow perhaps, that must be able to pierce anything. It is a constant, there are no varying elements." He paused. "As for those runes that are not there when you sense for them, it is because they are not truly runes, but more precisely pictures, or drawings if you will. They are tattoos, when they were placed there was no effort or concentration other than that of drawing them accurately. If there is no effort to use it, a rune is still only a line of ink." He kneaded his upper legs with his knuckles. He was not as flexible as he once was, and his muscles protested even at the morning's exercises. His pause indicated that the youth could add any further questions. Apparently the other understood, because his mouth opened to ask another question.
"If they aren't actually runes and don't do anything, why bother with them at all? Seems almost stupid to me." His tone had a slight edge. He was not even certain why it was like that. He was slightly tired. It could be that he is just a teensy bit cranky from sleep deprivation. But that was beside the issue at hand, which was the theoretic and practical aspects of magery.
Kevesk chuckled and shook his head. He remembered feeling like that all too well. He was going to have to lead the boy through it slowly.
"Well, Derrl, you must remember, I'm not as spry as you, and my memory is not as it used to be. That sort of thing does happen as you get older. And even so, with all the different variations of runes, it helps to have a reminder as to which ones are which of the more useful ones. You can get unexpected and frequently unpleasant results when you make even the tiniest error in calling forth energies with a rune." He laughed out loud now. Derrl nodded. He understood what the old man was saying. A bell sounded the hour outside and he realized that he had spent most of the morning sitting in talk. His eyes grew wide as he jumped up off the pallet and dashed out the door.
"SHIT! I'm late! Mensk will have my hide for this." He was halfway to the door as he called over his shoulder, "I'm at 'The Pint Alehouse' if you need me, that's where I am. Don't know when I'll be back." The words drifted to the mage as the sprinting form disappeared.