 definition will have advanced micro- and macrop- ositioning and direction sensing capabilities combined with extended audio (voice and music) and image-capture capabilities combined with extended audio and display and text output ca- pabilities plus access to server-side storage (the web) plus access to network resident rendering, filtering and processing power. Returning to our Big Ben example, Big Ben is an object with a unique audio signature. Other objects and places have similar but different signatures, the sea side for example, a concert hall, an airport. We mentioned earlier that audio signatures make potentially good ring tones - Big Ben or the Westminster Peal. If you fancy church bells as ring tones you will be interested in the relevant object metadata tag. Consider the effect of bells rung together in a peal rather than singly, in English changes - with each bell striking a fixed interval, usually 200 to 250 milliseconds after the previous one. Peals of bells can sound very different in character and the effect is influenced by many factors; the frequency and amplitude of the bells' partials, considered individually and as a group; how they are clappered; and rather critically, the building in which they are being rung' (from a guide to campanology - the harmonic science and mechanics of bell ringing). A paper on combinatorics, a branch of discrete mathematics with bell ringing as an example explores this topic further.3 Objects and places and spaces similarly have unique visual signatures. These can be object specific, The Statue of Liberty for example, or general, the seaside. A seascape will generally consist of some sky (usually grey in the UK), some sea (usually grey in the UK) and sand (usually grey in the UK). The image statistics will have certain recognisable ratios and certain statistical regional boundaries and there will also be a unique audio signature. Object and place and visual signatures come 'for free' from the autoexposure, autocolour balancing and autofocusing functions in higher