There's the tree with the branches that everyone sees, and then there's the upside-down root tree, growing the opposite way. So Earth is the branches, growing in opposing but perfect symmetry. The branches don't think much about the roots, and maybe the roots don't think much about the branches, but all the time, they're connected by the trunk, you know?
Gabrielle Zevin (2016). “Elsewhere”, p.69, Bloomsbury Publishing