prologues:=2; 
beginfig(1);
  u:=0.025cm;
  right:=(u,0);
  up:=(0,u);
  pair origin, bottom_right, top_left;
  origin := (320.u,860.0u);
  bottom_right := (580u,860u);
  top_left := (320u,1060u);
pickup pencircle scaled 1;
  draw origin--bottom_right;
  draw origin--top_left;
label.lft(btex $V$ etex,top_left);
label.bot(btex $\gamma$ - consumer concert threshold etex, bottom_right);
  pair a[];
  a[0] = .9[origin,top_left];
  a[1] = .8[origin,bottom_right];
  draw a[0] -- a[1] withcolor green;
  a[2] = .75[origin,bottom_right];
  a[3] = whatever[a[0],a[0]+right]=whatever[a[2],a[2]+up];
  draw origin--a[3] withcolor red;
  label.rt(btex $2\gamma$ - record company revenue etex,a[3]);
  a[4] = .4[a[2],a[3]];
  a[5] =.2[origin,bottom_right];
  a[6] = .3[a[4],a[5]]+15up;
  a[7] = .6[a[4],a[5]]+20up;
  path b;
  b = a[4]..a[6]..a[7]..a[5];
  draw b;
endfig;
end