Decide, whether exist tetrahedrons T, T′ with walls S1, S2, S3, S4 and S1′, S2′, S3′, S4′, respectively, such that for i=1,2,3,4 triangle Si is similar to triangle Si′, but despite this, tetrahedron T is not similar to tetrahedron T′. 3D geometrytetrahedronsimilarityPolandgeometry