The formula as metrical building block
A formula is a group of words regularly used under the same metrical conditions to express a given essential idea, such as 'swift-footed Achilles' or a line-opening that fits one slot of the verse. Singers do not choose words one by one; they reach for ready-made phrases already shaped to the meter, which makes rapid composition under performance pressure possible. Formulas also exist as substitution systems, patterns in which one word can be swapped to generate new lines on the same template.
