anchor.diff:  	
   	double get baseLight => 0.0;
   	Tile get customUp => feature.tile;
  +	Tile get customDown {
  +		for (Feature f in features) {
  +			if (f is FeatureMineshaft) {
  +				return (f as FeatureMineshaft).innerTile;
  +			}
  +		}
  +		return null;
  +	}
   	
   	bool get outdoors => false;
   	bool get underground => true;
  
positive.code: 	bool canMakeOn(Tile tile) => tile.outdoors;
  }
  
  class TileMineshaft extends FeatureTile {
  	TileMineshaft(FeatureMineshaft feature) : super(feature) {
  		maxFeatureSpace = 10;
  
negative.code: 	new RecipeHut(),
  	new RecipeCraftingTable(),
  	new RecipeMineshaft(),
  	new RecipeMineshaft2(),
  	new RecipeTunnel(),
  	new RecipeTorches(),
  ];