"It's supposed to be something that's very evocative of the thousands of years that have passed since these caves were first explored and the paintings were first made. And also obviously something that’s quite relevant to the current storyline because it’s about how these two disparate peoples united to defeat the common enemy," he said. "One of the things we learn from these cave paintings is that the White Walkers didn’t come up with those images, they derived them from their creators, the Children of the Forest. These are patterns that have mystical significance for the Children of the Forest. We're not sure exactly what they signify, but spiral patterns are important in a lot of different cultures in our world, and it makes sense that they would be in this world as well."