2+2−2\sqrt{2+\sqrt{2-\sqrt{2}}}2+2−2
2+2+2\sqrt{2+\sqrt{2+\sqrt{2}}}2+2+2
2−2−2\sqrt{2-\sqrt{2-\sqrt{2}}}2−2−2
2−2+2\sqrt{2-\sqrt{2+\sqrt{2}}}2−2+2