In our preliminary visual trajectory analysis, we were readily able to find cis double bonds near the membrane surface (Fig. ). By contrast, trans double bonds were only rarely observed at the membrane surface. To quantify this finding, we measure the distribution of the phosphates as well as the atoms involved in double bonds, using the phosphates themselves as a proxy for the membrane surface. We find in Fig. that the cis double bonds are on average closer to the membrane surface than trans double bonds. While the position of the maximum probability shifts by less than 2 Å, the asymmetric distribution for atoms in cis double bonds places them occasionally very close to the membrane surface.