The geodesic graph of Riemannian spaces all geodesics of which are orbits of 1-parameter isometry groups is constructed by J. Szenthe in 1976 and it became a basic tool for studying such spaces, called g.o. spaces. This infinitesimal structure corresponds to the reductive complement m in the case of naturally reductive spaces. The systematic study of Riemannian g.o. spaces is started by O. Kowa...