Imagine the long-term and almost periodical interaction of gravitation waves with existing distribution of atoms (mostly hydrogen) in deep space. Billions of years of interaction can form a repetitive structure of atoms in huge volume (in 3-Dimesions), with some statistical deviations which can be caused by irregularities of gravitation waves.
Can this repetitive structure (in absence of near source of gravitation) represent some properties of Metamaterials?