Gdog's Cosmic Rock uses pinback buttons to illustrate the history of rock music. From the creator:
'In 2005, I had an idea about creating a Rock n Roll Tree out of buttons from bands. I wanted the layout, as best as I could, to place the bands in chronological order based on their first EP, Album or CD. So, I created a list of bands with the help of friends and started collecting various band's buttons. I received these buttons from all over the world. Most of the earlier bands, I found in Europe. I have to admit, I've cursed myself for even starting this project several times! Five years later, I finally had enough buttons to actually create the poster. I tried to keep different genres to capture the explosion of Rock n Roll music. My apologies in advance for any band left off.