+bppM = epp4 + [0,1] * lid_gap_z;
+bppN = [ 0.5 * (epp0[0] + epp4[0]), bppM[1] ];
+bppR = [ bppN[0] + lid_buttoncover_gap, -button_cutout_depth ];
+bppS = [ epp1[0], bppR[1] ];
+bppQ = [ bppM[0], bppR[1] - lid_buttoncover_overlap ];
+bppP = bppQ + [0,1] * lid_buttoncover_gap;
+bppO = [ bppN[0], bppP[1] ];
+bppL = lpp10 + [1,0];
+bppK = [ bppL[0], bppN[1] ];
+bppJ = [ bppN[0], bppL[1] ];
+