// -*- C -*-
+arch_height = 24;
+arch_width = 75;
+end_width = 25;
+
+arch_thick = 5;
+
+// computed
+
+arch_alpha = atan(arch_height / (arch_width/2));
+arch_beta = 2*arch_alpha;
+echo(arch_alpha,arch_beta);
+arch_in_rad = arch_width/2 / sin(arch_beta);
+arch_to_chord = arch_in_rad * cos(arch_beta);
+
+//arch_to_chord = (arch_width/2)*(arch_width/2)/arch_height;
+//arch_in_rad = arch_to_chord + arch_height;
+//arch_in_rad2 = sqrt(arch_to_chord*arch_to_chord +
+// (arch_width/2)*(arch_width/2));
+
+//echo(arch_in_rad, arch_in_rad2);
+
+module ArchProfile(){
+ intersection(){
+ translate([-200,0])
+ square([400,200]);
+ translate([0,-arch_to_chord]){
+ difference(){
+ circle(arch_in_rad + arch_thick, $fa=0.1);
+ circle(arch_in_rad, $fa=0.1);
+ }
+ }
+ }
+ %square([arch_width/2,arch_height]);
+}
+
+ArchProfile();