1.Kc8 threat 2.Sb7+ any 3.d8S
1...Be6 2.Qh2+ Rf4 3.Qxf4 ; 2...Re5 3.Qxe5
1...e5 2.Sxb5+ any 3.Qb4
1...Rd5 2.Qf4+ e5 3.Qxf6 ; 2...Re5 3.Qxe5
(after 1..e6 the threat gives the additional mate 2..Ke7 3.d8Q)
A cycle of interferences. The bishop interferes with the pawn, the pawn interferes with the rook, and the rook interferes with the bishop. Interest is added by the variety of reasons why the defences work.