// -*- C -*-

main_sz = 20;

wall_th = 3;

front_fullsz = 10;

back_tot_l = 30;
back_cut_l = 4;
back_cut_w = 10;
back_prong_w = 3;

module MidPlan(){
  polygon([[0,            0],
	   [0,            main_sz],
	   [wall_th,      main_sz],
	   [wall_th,      wall_th],
	   [main_sz,      wall_th],
	   [main_sz,      0]]);
}

module FrontPlan(){
  halfway = (front_fullsz + main_sz)/2;
  polygon([[0,            0],
	   [0,            main_sz],
	   [front_fullsz, main_sz],
	   [main_sz,      front_fullsz],
	   [main_sz,      0]]);
}

module BackPlan(){
  sqmid = main_sz * sqrt(0.5);
  prlen = back_tot_l - sqmid;
  prx = 0.5*back_cut_w + back_prong_w;
  difference(){
    union(){
      square(main_sz);
      rotate(-45) translate([-prx, sqmid])
	square([prx*2,prlen]);
    }
    rotate(-45) translate([-back_cut_w/2, back_tot_l-back_cut_l])
      square([back_cut_w, back_cut_l+1]);
  }
}

//MidPlan();
//FrontPlan();
BackPlan();