// -*- C -*-

module FArcSegment_mask(beta) {
  for (i=[0 : 0.75 : 3]) {
    rotate(i*beta/4)
      polygon([[0, 0],
	       [1, 0],
	       [cos(beta/4), sin(beta/4)]]);
  }
}

module FArcSegment(xc,yc,inrad,outrad,alpha,delta) {
  translate([xc,yc]) {
    intersection() {
      difference() {
	circle(r=outrad);
	circle(r=inrad);
      }
      rotate(alpha) scale(outrad*2) {
	FArcSegment_mask(delta);
      }
    }
  }
}

tubeheight = 30;
tubewidth = 15;
mainthick = 4;

clipthick = 2;
clipang = 120;

stemlen = 50;

topwidth = 30;

hookinrad = 7.5;
hookcurl = 60;
hookwidth = 4;

tuberad = tubewidth/2;
bend = atan(tuberad/stemlen);
mainoutrad = tuberad + mainthick;
hookoutrad = hookinrad + hookwidth;
hookcy = stemlen - hookoutrad;

module Plan(){
  dy = tubeheight - tuberad*2;
  FArcSegment(0, dy, tuberad, mainoutrad, -1, 181);
  FArcSegment(0, 0,  tuberad, mainoutrad, -bend, bend+1);
  translate([tuberad, 0]) square(center=false, size=[mainthick,dy]);
  FArcSegment(0, 0, tuberad, tuberad + clipthick, 360-clipang, clipang+1);
  rotate(-bend) translate([tuberad, 0]) mirror([0,1])
    square(center=false, size=[mainthick, stemlen/cos(bend)]);
}

module Elevation(){
  FArcSegment(0, -hookcy, hookinrad, hookoutrad, 180, 90+hookcurl);
  translate([-hookoutrad*sqrt(0.5), -(stemlen+10)]) mirror([1,0])
    square(center=false, size=[topwidth, stemlen + tubeheight + 20]);
}

Plan();
translate([50,0])
  Elevation();