void display(void)
{  glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   glMatrixMode(GL_MODELVIEW);
   
   for (int i=0; i <= 100; i++) {
         glRotatef(90, 1, 0, 0);
         glutSolidSphere (0.5, 400, 400);
         glLoadIdentity();
         glFlush ();
                                }
   
        
      
}