This problem investigates a square plate with sides of length 2 centered at the origin under plane stress. Uniform normal tensile stresses of sigma_x in the x-direction and sigma_y in the y-direction. There are no shear stresses. As the problem is symmetric only a quarter of the plate is modelled. The analytic strains for this case are e_x = sigma_x/E - nu.sigma_y/E and e_y = sigma_y/E - nu.sigma_x/E where nu is Poisson's ratio and E is Young's modulus. For this case E=200 GPa, nu=0.3, the stress in the x-direction is 10 kPa and the stress in the y-direction is 5 kPa. This gives analytic displacements of 0.0425 micrometers in the x-direction and 0.010 micrometers in the y-direction. Compare this with the equivalent plane strain example in example_431.