Phonetic transcription can be likened to an infinite palette of paints. It is possible, in theory, to depict in phonetic script differences as subtle as the most finely attuned ear can hear. To achieve this, there is a large inventory of symbols, including a set of diacritics, which act as pointers to exact articulatory positions or ways of making a sound. Thus, to give just two examples, the diacritic [ + ] written beneath a symbol indicates tongue further forward and [:] written to the right-hand side of a symbol means of greater duration. A full set of symbols, including the diacritics, can be found on the IPA chart on page xii.