Good border for fun windows which need that extra something to make them look special.  Stained glass hearts (about half inch thick and all rouded on the front, but flattish on the back, were purchased in a back from Michaels and Hobby Lobby..but are likely available online and elsewhere.  I lightly ground the edges of the hearts before copper foiling them, and also used a thick copper foil to make sure that some of the edge bent over the rounded parts to insure that the heart stayed in place when soldered.