0) to (0+0,-0+0) to (0+0,-0+0+0); (0+0,-0+0+0) to (0+0,-0+0+0+0) to (0+0+0,-0+0+0+0+0);  at (-0.0,-0.0) [$\alpha + \beta$]{}; at (0.0,-0.0) [$\alpha + \beta$]{}; at (-0.0,0.0) [$\alpha$]{}; at (0.0,0.0) [$