xy = 
  [  0.951057      0.309017;    
  0.224514      0.309017    ;
 -0.951057      0.309017    ;
 -0.363271     -0.118034    ;
  0.587785     -0.809017    ;
  0.363271     -0.118034    ;
  0.612323E-16   1.00000    ;
 -0.224514      0.309017    ;
 -0.587785     -0.809017    ;
 -0.701660E-16 -0.381966 ]