During continued plastic deformation of a polycrystalline metal, certain crystallographic planes tend to rotate with respect to the direction of the greatest principal strain, and the texture of the metal assumes a fibrous appearance. The phenomenon is similar to that of a single crystal in which the slip planes tend to rotate in such a way as to become parallel to the direction of the maximum principal strain. Since the individual crystal grains in a polycrystalline aggregate cannot rotate freely due to their mutual constraints, the development of a preferred orientation in a polycrystalline metal is much more complex. As a result of progressive cold work, an initially isotropic metal therefore becomes anisotropic, and its mechanical properties vary with the direction. The yield strength of the metal in the direction of mechanical working may be greater or less than that in the transverse direction, depending on the type of preferred orientation that is produced by cold work. In a cold rolled sheet of brass, for instance, the tensile yield stress transverse to the direction of rolling can be considerably higher than that in the rolling direction. Although anisotropy and the Bauschinger effect always occur together, the latter can be largely removed by mild annealing, while the former can be altered only by carrying out the heat treatment above the recrystallization temperature.