Let Lambda be a finite-dimensional algebra over an algebraically dosed
field. Notions of a triangle and a diamond of Lambda-modules satisfyi
ng some orthogonality conditions are introduced and studied in this No
te. It is proved that the existence of a triangle or a diamond of Lamb
da-modules implies that Lambda is of non-polynomial growth. The conver
se is proved for strongly simply connected algebras and for special bi
serial directed algebras.