Zend_Form utilizes the decorator pattern in order to render elements and forms. Unlike the classic decorator pattern, in which you pass an object to a wrapping class, decorators in Zend_Form implement a strategy pattern, and utilize the metadata contained in an element or form in order to create a representation of it

Don't let the terminology scare you away, however; at heart, decorators in Zend_Form are not terribly difficult, and the mini-tutorials that follow should help you along the way. They will guide you through the basics of decoration, all the way to creating decorators for composite elements.