Once the existence of the strange phenomenon was confirmed for everyone, E. Altshuler and a number of collaborators performed a systematic study in Havana, which was then jointly published with Bassler. Further work has been done to understand in more detail the phenomenon, and it has been found in other sands from different parts of the world. However, the connection between the physical, chemical (and possibly biological) properties of the grains in a specific sand, the nature of the inter-grain interactions, and the emergence of the revolving rivers is still an open question.