Old town, Tallinn, 2007 Light and sound installation Galaxies (among them our Milky Way galaxy and big Andromeda galaxy) converge into various abundant clusters and groups. Estonian astrophysicist Jaan Einasto in co-operation with other scientists from Tartu Observatory discovered a dark or perhaps an invisible matter around the giant galaxies. Later on the scientist group came up with the concept of superclusters whereupon they recognized that the universe is comb-shaped. It was proved that the clusters which belong in superclusters form quite an organized network. The network is almost right-angled and the diameter of its cell is around 120