font_identifier:="xhslu20";
mode_setup;
font_size 20pt#;
thick#:=1pt#;
stepwidth#:=1/8designsize;% -> \internote
define_pixels(stepwidth);
define_blacker_pixels(thick);
picture save_pic;
numheights:=16;
numlengths:=8;%(20-90pt)

code=-1;
for j=1 upto numlengths:
  slength#:=(j+1)*10pt#;
  define_pixels(slength);

  for i=1 upto numheights:
    beginchar(incr code, slength#, 0, 0);
      x1=y1=0;x3=slength;y3=2y1'=-i*stepwidth;
      x1'=.5x3;z3'-z1'=whatever*dir(angle(z3-z1)+90);
      if x3>-y3:y3'=0;else:x3'=slength;fi
      z2=.5[z3',z1'];
      penpos1(thick,90);
      penpos2(2/3thick,(angle(z3-z1)+90));
      penpos3(.15thick,(angle(z3-z1)+90));
      penstroke z1e..z2e..z3e;
      pickup pencircle; draw z1..z2..z3;% draw z1--z3; draw z1'--z3';
      save_pic:=currentpicture;
    endchar;

    beginchar(128+code, slength#, 0, 0);
      currentpicture:=save_pic reflectedabout((.5slength,0),(.5slength, 1));
    endchar;
  endfor

endfor
end