float a  = (num_x-1)/2 + (6 * sin( 1.3 * c * 10  ) );
   float aa = (num_y-1)/2 + (6 * cos( 1.3 * c * 10  ) );

   float red_size=30;
   float scale_x = 1;
   float scale_y = 1;

   float aaa = 255-((red_size)*sqrt(((a-x)*(a-x)*scale_x)+((aa-y)*(aa-y)*scale_y)));