As for topological phases, bulk is usually hidden in the sense that non trivial topological numbers of the bulk are hardly observed directly by standard experiments. Then observation of edge states reflecting such a non-trivial bulk is a key experiment. This is the bulk-edge correspondence. Here we are proposing possible alternative. Dynamical evolution of localized many particle wave packets reflects such a non-trivial bulk without any boundaries. Look at our recent paper “Detecting bulk topology of quadrupolar phase from quench dynamics” by Tomonari Mizoguchi, Yoshihito Kuno, and Yasuhiro Hatsugai, published in Physical Review Letters (Jan. 8, 2021). Then this bulk observation implies the edge/corner states when the system is with suitable boundaries. See also arXiv:2008.01924.