URL: https://www.researchgate.net/publication/362683599/figure/fig5/AS:11431281078988342@1660442923666/In-red-colour-the-ellipsoid-with-equation-xSx-mx0documentclass12ptminimal.png
URL2: https://www.researchgate.net/figure/In-red-colour-the-ellipsoid-with-equation-xSx-mx0documentclass12ptminimal_fig5_362683599
