+// hinge plan
+hp_rn = hingescrew_nut_dia/2;
+hp_r2_min = hp_rn + lever_cover_th;
+hp_rs = hingescrew_shaft_dia/2;
+hp_r1_min = hp_rs + hingemount_th;
+
+hp_r1 = max(hp_r1_min, hp_r2_min);
+hp_r2 = hp_r1;
+
+hppU = lpp13;
+hppS = epp2o + [0,-1] * case_th_bottom;
+hp_k = 0.5 * (hppU[1] - hppS[1] + foldover_gap);
+
+hppM = [ epp4[0] - foldover_lever_gap - hp_r2,
+ 0.5 * (hppU + hppS)[1] ];
+hppT = [ hppM[0], hppU[1] - hp_r1 ];
+hppB = hppT + [0,-1] * hp_k;
+
+hppE_y = epp2o[1] - case_th_bottom + hp_r1;
+hppE_x = hppB[0] + (hppB[1] - hppE_y) * hinge_base_slope;
+hppE = [ hppE_x, hppE_y ];
+
+// hinge elevation x coords
+
+hingescrew_portion_len =
+ 0.5* (hingescrew_shaft_len - hingescrew_nut_thick - hinge_x_gap);
+
+hex20 = max(epp2o[0],
+ phone_cnr_rad,
+ kppd[0] + hingescrew_head_th + keeper_gap_x_holes);
+hex21 = hex20 + hingescrew_portion_len;
+hex22 = hex21 + hinge_x_gap;
+hex23 = hex22 + hingescrew_portion_len
+ - hingescrew_nut_thick; // bodge, need to divvy this up more sensibly
+hex24 = hex20 + hingescrew_shaft_len + hinge_x_postscrew_gap;
+//echo(hex20, hex21, hex22, hex23, hex24);
+//echo(hingescrew_portion_len);
+
+// catch
+
+cppJ = [ epp4[0] + catch_thickness, lpp10[1] ];
+cppA = cppJ + [lid_gap_x, -lid_gap_z];
+cppB = [ epp0[0], cppA[1] ];
+cppP = [ epp4[0], cppJ[1] ];
+
+cppS = cppJ + [0,-1] * catch_len;
+cppD = [ cppA[0], cppS[1] + catch_slop ];
+cppC = [ cppB[0], cppD[1] ];
+cppT = cppS + [1,0] * catch_depth;
+cppU = cppT + [0,-1] * catch_height;
+cppV = [ cppS[0], cppU[1] - catch_depth ];
+
+cppR = 0.5*(cppP + cppJ);
+
+cp_rQ = 0.5 * (cppJ[0] - cppP[0]);
+cppQ = [ cppR[0],
+ cppV[1] - (catch_finger_height - cp_rQ) ];
+cppF = [ cppV[0] + catch_finger_depth, cppC[1] ];
+
+// prop recess in case
+
+prop_x_pos = phone_width/2;
+
+prop_recess_hw = 0.5 * prop_main_width + prop_side_gap;
+
+prc_r1 = prop_end_dia/2;
+prc_r3 = prc_r1 + prop_recess_slop;
+
+prcp2 = [ epp4[0] + prop_buildout_less,
+ case_bottom_z ];
+
+prop_caserecess_buildout_r = -1; // prcp2[0] - epp2o[0];
+
+prcp1 = [ epp2o[0],
+ epp2i[1] - prc_r3 ];
+
+// prop recess in lid
+
+prl_r10 = prop_end_dia/2;
+prl_r10o = prl_r10 + prop_recess_slop;
+
+prlp10 = lpp10 + [1,1] * prl_r10o
+ + [1,0] * prop_lidrecess_behind
+ + [0,1] * prop_recess_under;
+
+// prop
+
+prpp10 = [0,0];
+prpp11 = [0, prop_taper_len];
+
+prp_r10 = prl_r10;
+
+// ---------- modules ----------