The currency sign is the diplomat of punctuation, a mark whose entire purpose is to avoid taking sides. It means, simply, some currency, unspecified, a little symbol that stands in for money in general without ever committing to whose money it is. Where the dollar sign, the pound sign, and their many cousins each speak for a particular nation's coin, this one deliberately speaks for none. It is a placeholder, a courteous shrug in symbol form, present precisely so that no single currency's mark has to be.

Its origin lies in the practical diplomacy of early computing. In the 1970s, as engineers assembled the character sets that would let machines around the world share text, they ran into a delicate problem. Every country wanted its own currency symbol to occupy the limited slots available, and there was not room, nor goodwill, for all of them. The currency sign was proposed as a peaceful compromise, a neutral mark that countries could agree on so they would not have to fight over whose symbol got a precious code point. In some national variants of the ISO 646 standard, it even shared a slot with the dollar sign, sitting in the position that other countries reserved for their own money, a single space doing double duty depending on where the machine happened to be.

The result is a small marvel of self-reference that the exhibit finds quietly funny. Here is a symbol whose whole job is to stand in for a symbol, a mark that means nothing more specific than there should be a currency mark here. It is an artifact of internationalisation, a byproduct of the effort to make many languages and many moneys coexist in the same limited alphabet of bytes. Most characters point outward, at a sound or a thing or a sum. This one points sideways, at the very idea of a currency symbol, holding a place open for whichever real money the situation eventually demands. It is punctuation's way of writing a blank cheque, and then declining to fill in the name of the bank.