What does the world roll by mean?

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A few lone trees have started to show up in the distance, towering wild pines with trunks as thick as barrels. Without my noticing, the trees grow slowly more numerous and, in that creeping way that landscapes change, it isn’t long until they span both sides of the road, encapsulating us in a deep, bright forest. Realising I’ve recorded everything of substance, and with Rob concentrating on the drive, I have no choice but to lay back in my seat and watch the world roll by. Despite the pervasive strangeness of the Left/Right Game, there is beauty on the road. Under the light shade of the canopy, the smell of pine needles permeating the still air, I actually feel myself starting to relax.