public override void nextTile()
{
if (tx == ntX - 1 && ty == ntY - 1)
{
// Already at last tile
throw new NoNextElementException();
}
else if (tx < ntX - 1)
{
// If not at end of current tile line
setTile(tx + 1, ty);
}
else
{
// First tile at next line
setTile(0, ty + 1);
}
}