Ashtray-Cup / Cup

If there is no one smoking in your family, but some smoking guests come.
If you have no ashtrays in your house.
If one day many friends come to your house but the ashtrays are not enough, what would you do?
No matter whether there is some one in your family smoke, you should have at least one ashtray in your home.
So this idea which is a combination of glass and ashtray is exactly meet your needs.
There is no doubt that every family has a cup. If your cup is this one, when you encounter these situations above, the only thing you have to do is put it upside down.