Weird rules here.
France-UK
UK-France
Belgium-UK
UK-Belgium
Netherlands-UK
UK-Netherlands
(Before the UK became Schengen)
Italy-San Marino
San Marino-Italy
Italy-Slovenia
Slovenia-Italy
Italy-Vatican
Vatican-Italy
Italy-Greece
Greece-Italy
Greece-Turkey (not Cyprus)
Turkey-Greece (not Cyprus)
Belgium-Netherlands-Germany, standing in 3 countries at once.
Being within a country, within another country etc (Belgium and the Netherlands)
Israel-Egypt
Egypt-Israel
Serbia-Kosovo
Kosovo-Serbia
Skipping all the regular EU countries.