I admire these lovely hearts both from the art and engineering points of view. These richly-textured encased hearts fit inside each other like Russian Matrioshka dolls. They are made by an artist from Colorado, Tejae Floyde, and can be found in TejaesArt.etsy.com shop and her Flickr photo album.
I also love Tejae's idea of pocket hearts. Imagine finding a heart like that in your pocket (placed there secretly by a person who loves you)!
Find out more about tejae and her art in her blog, tejaesart.blogspot.com.