public void generateMineshaft(int x,int y){
        int length = rand.nextInt(SIZE/2);
        boolean up = rand.nextBoolean(); // false if in left-right 
        for(int i=x;i<length+x;i++){
            if(i>=SIZE || y+1>=SIZE || y+2>=SIZE) return;
            if(up){
                world[y][i] = TileType.WOOD;
                world[y+1][i] = TileType.AIR;
                world[y+2][i] = TileType.WOOD;
            }else{
                world[i][y] = TileType.WOOD;
                world[i][y+1] = TileType.AIR;
                world[i][y+2] = TileType.WOOD;
            }
        }
    }