Verbals comprise a special set of non-finite forms present in the English language. They can be used in a variety of ways and present certain specific structures. Bearing this in mind, read the text below:

Prologue

Hear me! We have heard of Danish heroes,

Ancient kings and the glory they cut

For themselves, swinging mighty swords!

(Source: RAFFEL, Burton. Beowulf. New York: Signet Classics, 2008, p.3)

The highlighted element in the text is an example of a: