I want to do this. Players can not affect the other players, but can affect the environment, changing and adding to it. This calls for such an opportunity. The player should be able to make global changes, which sees the other player when he appears on the same card.
How can I make this? To have files with the characteristics of each card and write to them the coordinates of all properties per?
Another problem in this case, it reads these files. If it will boot room, then to see the changes that need to logout and login again. But what if the other player is still there inside? So you need to updated bathroom after some passage of time? All of this is an interesting problem.