data x(drop=pi tau);
   pi = constant('pi');
   do tau = -pi to pi by pi / 100;
      x = 0.8 * cos(tau);
      y = 0.8 * sin(tau);
      output;
   end;
   g + 1; 
   do tau = -pi to pi by pi / 2;
      x = 0.9 * cos(tau);
      y = 0.9 * sin(tau);
      output;
   end;
   g + 1; 
   do tau = -pi / 4 to 7/4*pi by pi / 2;
      x = 0.7 * cos(tau);
      y = 0.7 * sin(tau);
      output;
   end;
   g + 1; 
   do tau = 0 to 2 * pi by 2 * pi / 8;
      x = 0.15 * cos(tau - pi / 8);
      y = 0.15 * sin(tau - pi / 8);
      output;
   end;
   g + 1; 
   inc = 2 * pi / 32;
   do tau = 0 to 2 * pi - 0.5 * inc by inc;
      xx  = cos(tau);
      yy  = sin(tau);
      x = 0.33 * xx;
      y = 0.33 * yy;
      output;
      x2 = cos(tau + inc);
      y2 = sin(tau + inc);
      m = -(x2 - xx) / (y2 - yy);
      t1 = mean(xx, x2);
      t2 = mean(yy, y2);
      xx = (t1 + ifn(t1 gt 0, -1, 1) * sqrt(0.15 / (1 + m * m)));
      yy = m * (xx - t1) + t2;
      x = 0.33 * xx;
      y = 0.33 * yy;
      output;
      end;
   output;
run;

%let o = offsetmin=0 offsetmax=0;
proc sgplot data=x aspect=1 noautolegend;
   title 'Equated';
   refline -.75 to 0.75 by .25 / axis=x;
   refline -.75 to 0.75 by .25 / axis=y;
   polygon y=y x=x id=g / group=g lineattrs=(thickness=5);
   xaxis &o;
   yaxis &o;
run;   

proc sgplot data=x noautolegend;
   title 'Not Equated';
   refline -.75 to 0.75 by .25 / axis=x;
   refline -.75 to 0.75 by .25 / axis=y;
   polygon y=y x=x id=g / group=g lineattrs=(thickness=5);
   xaxis &o;
   yaxis &o;
run;