public boolean isAccessible(){
	// rock, void and spawn are not accessible.
	// grass, rubidium, explosium, scrap are accessible.
	if(tileType == TileType.GRASS || tileType == TileType.RUBIDIUM
	   || tileType == TileType.EXPLOSIUM ||tileType == TileType.SCRAP){
	    return true;
	}
	else {
	    return false;
	}
    }