That's a pretty neat approach, maybe I should do something similar. Originally I color-coded the words (based on frequency) but having a gradual spectrum applied to the edges feels a lot more intuitive.
Dunno about the arrow tips, but seems like the slowly changing colors enable you to quite easily follow the original order of the lyrics. (except if the reader is color blind)
Each colour is a verse, fading through the spectrum.
An unfilled arrowhead shows a transition between words in a line of a verse, a filled arrowhead shows a transition between lines.