82                 struct Position
 83                 {
 84                         float x;
 85                         float y;
 86                         
 87                         Position()
 88                         {
 89                                 x = y = 0;
 90                         }
 91 
 92                         Position(float nx, float ny)
 93                         {
 94                                 x = nx;
 95                                 y = ny;
 96                         }
 97                 };