"World is place, no?" Ffion asks, confused. "Rhydaber is a world, the Library is a world?" "But can you walk from Rhydaber to the Library?" Colle asks, before Inric can say anything. "No," he confirms her thoughts. "We defined worlds by their magic - its flux, form and flow. Wherever Rhydaber is physically, its magic is sufficiently different to classify it as another world." "But there's two magics in Rhydaber," Ffion says, having grasped just enough of the explanation to persist. "Yes. Two forms, and probably two flows. That is why it is so interesting."