some messed up version Mohr's Circle

 Px1 = Sigma1;
            Py1 = 0;
            Px2 = C;
            Py2 = 0;
            Px3 = Sigma_x;
            Py3 = Shear_xy;

            %[Px1, Py1] = dataextractor(point1);
            %[Px2, Py2] = dataextractor(point2);
            %[Px3, Py3] = dataextractor(point3);

            v1 = [Px2 - Px1, Py2 - Py1];
            v2 = [Px3 - Px1, Px3 - Py1];

            angle_rad = atan2(det([v2; v1]), dot(v2, v1)) ;
            angle_deg = (rad2deg(angle_rad))/2;
            Theta_p1 = angle_deg;
            Theta_s1 = Theta_p1 - 45;

            PxD1 = Sigma2;
            %[PxD1, Py1] = dataextractor(point4);
            %[Px2, Py2] = dataextractor(point5);
            %[Px3, Py3] = dataextractor(point6);

            v3 = [Px2 - PxD1, Py2 - Py1];
            v4 = [Px3 - PxD1, Px3 - Py1];

            angle_rad = atan2(det([v4; v3]), dot(v4, v3)) ;
            angle_deg = (rad2deg(angle_rad))/2;
            Theta_p2 = angle_deg;
            Theta_s2 = Theta_p2 - 45;