public Mat getNext(int aMazeLevel) {
   Mat lResult = null;
   Mat lFound = new Mat();
   lFound.material = fMat;
   lFound.data = baseMaterialData;
   for (Mat lMat : this) {
     if (lMat.mazeLevel < 0 || lMat.mazeLevel == aMazeLevel) {
       lFound = lMat;
       if (fRnd.nextInt(100) < lMat.chanceToUse) {
         lResult = lMat;
       }
     }
   }
   return lResult == null ? lFound : lResult;
 }