Quilling is the art of using scrolled paper to make 3D artistic compositions. Wikipedia has some info, but better is to google 'quilling' to look for images, many of which are stunning.
The Quilled Heart stamp is the 2016 entry into the USPS Love series. Digital images of this stamp do seem more vibrant and show more detail than the actual stamp, although it has grown on me.
For more stamps with a Q theme, head over to browse the links at Sunday Stamps.