Most carols follow a more or less standard format: they begin by exalting the relevant religious feast, then proceed to offer praises for the lord and lady of the house, their children, the household and its personnel, and usually conclude with a polite request for a treat, and a promise to come back next year for more well-wishing. Almost all the various carols are in the common dekapentasyllabos (15-syllable iamb with a caesura after the 8th syllable) verse, which means that their wording and tunes are easily interchangeable. This has given rise to a great number of local variants, parts of which often overlap or resemble one another in verse, tune, or both. Nevertheless, their musical variety remains very wide overall: for example carols from Epirus are strictly pentatonic, in the kind of drone polyphony practised in the Balkans, and accompanied by C-clarinets and fiddles; just across the straits, on Corfu Island, the style is tempered harmonic polyphony, accompanied by mandolins and guitars. Generally speaking, the musical style of each carol closely follows the secular music tradition of each region.