data/level_list

   1 levels/level1.txt
   2 levels/level2.txt
   3 levels/level3.txt
   4 levels/level4.txt
   5 levels/level5.txt
   6 levels/level6.txt
   7 levels/level7.txt
   8 levels/level8.txt
   9 levels/level9.txt
  10 levels/levela.txt