No problem C-H.
There was a brand of vacuum cleaner here (who's name escapes me at the moment) that used a plug and socket configuration like that, to connect the mains cord to the cleaner.
A very similar configuration with offset center ground pin has been used for years here for extension leads on tools and similar appliances. The pins are much shorter though:
There are also versions without the ground pin which are reversible. They became quite common on double-insulated garden power tools:
[This message has been edited by pauluk (edited 10-05-2004).]