Living Design Fossils

Key today                                   Roman key

'[A] Living fossil is an informal term for any living species (or clade) of organism which seems to be the same as a species otherwise only known from fossils and has no close living relatives. These species have all survived major extinction events, and generally retain low taxonomic diversities'

Lets take the example of a key for now (though I do see the errors in the objects analyses) We have 'fossils' of keys from many periods of time (after 400bc). 'It is generally acknowledged that keys and locks were invented around 400 BC - probably by the Greeks.' [nokey.com/ankeymus.html]) The keys we use today would recognisable to the Greeks who first invented them. It is a design that has 'survived major extinction events' (as of this moment there isn't a reliable alternative, swipe cards are a good example of this) and has little if any close living relatives. What other Living Design Fossils surround us?