| I will discuss the problem of classification of finite complete families of incident planes in P^5. First i will present a construction of a complete family of incident planes of maximal cardinality 20 (a joint work with M.Donten-Bury, B.van Geemen, M.Kapustka, J. Wisniewski). Then show that the Morin problem is equivalent to the problem of classification of nodal (2,2) divisors in P^2xP^2. The methods consist of studying projective models of special hyper-Kaehler fourfolds. |