Stumpwork is an old English technique, popular in the 17th Century (I think, I should go and check on that, but it's about right). It has a lot of 3D stuff, which are built on either felt padding or wired elements. Generally stumpwork designs are flowers, animals or people.
This heart is a bit of mutated stumpwork, I haven't stuck with the "traditional" stitches or methods everywhere (I'm sure someone somewhere will get upset with me for that!
). Its all done in normal floss (DMC/Anchor) and the purple flames are made on wire. You do these separately and then add them in when they're already finished. It's actually really easy - there is only four seperate stitches: blanket stitch for the large blue flames; satin stitch for the solid blue flames, cross stitch for the heart and the purple flames are in needlelace (which is pretty much a detached buttonhole stitch).