A fabric in which the orientation of mineral grains is determined by their shape, so the fabric may be modelled by the shapes of various strain ellipsoids. Three tectonite fabrics are commonly used to demonstrate shape fabrics. L-tectonites, produced by uniaxial stretching with planar fabrics, correspond to prolate ellipsoids (see prolate uniaxial strain). S-tectonites, produced by flattening with planar fabrics, correspond to oblate ellipsoids (see oblate uniaxial strain). L–S-tectonites, produced by stretching and flattening with intermediate fabrics, correspond to triaxial ellipsoids.