Heart-shaped yo-yo’s?  What a wonderful idea! They’re mentioned and pictured both on Cyndi’s Layers Upon Layers and Chloe’s Tangled Thread.  (More yo-yo’s at Tangled Thread.)
Yo-yo’s always seem so popular whenever I mention them or I find them on other quilting and crafting sites.  These little shirred circles can be used for so many projects and have been around for ages. 
Noreen Crone-Findlay,  at Hankering for Yarn, always has some yo-yo ideas to share with us, too.  Here she shows us how to make a yo-yo circle.
 I wonder how someone first discovered they could make yo-yo’s.  Was it by accident or done deliberately?