"What is it you don't understand?" She leans on the table and smiles. "The division of magic," Tiero says. "I mean, I understand flux, but how are form and flow different? And what defines a form, why do some people use song and some use written magic? Do we just get to choose? Does the form affect the flow? And -" "Hold on, hold on," Kasivelieth says, and laughs. "There's a good explanation in the next chapter." She pulls another chair up to the table and sits down, flipping through the pages to find the right spot. "Flux, form and flow are all ways of describing the interaction between the mage and the innate magic within their world." "But Invarioneth can use magic on other worlds," Tiero says. "Yes, I know, we all can. You see..." Tiero bends over the book as she explains. Neither notice Anvar walking past, nor his doubletake when he sees them, nor his sudden irritated flush.