These are four mosaic coasters that, when you put them together, form a color wheel.
This was featured at the SAMA 2007 exhibition.
The work is byJulie Richey . You can find her work featured in Sonia King’s Mosaic Techniques and Traditions book.
http://www.oggettimosaics.com/index.shtml is the place to look if you want further details about Julie’s work, and classes are available if you should be in the Dallas area…