Talk:Warping functions

The Figure "Shear stresses in the cross section of an elliptical cylinder under torsion" seems wrong: there is no explanation, but seemingly the level curves represent the lines where the tangential stress tau has the same intensity. Given that in the Center the shear stress must be zero, it appears that the highest level is found at the two intersection of the contour with the major axis (horizontal). However is well known that the maximum stress is at the intersection of the contour with the minor axis (vertical). Please give a different explanation of the figure or correct it. Luca Bacchi