Shrinky Dinks is a children's toy and activity kit consisting of sheets of polystyrene which can be cut with standard household scissors. When heated, the cut shapes become about nine times thicker while their horizontal and vertical dimensions reduce to about one-third the original size, resulting in hard, flat forms which retain their initial color and shape. They reached the height of their popularity in the 1980s. Most sets are pre-printed with outline images of popular children's characters or other subjects, which are then colored in before baking. Shrinky Dinks were invented in 1973 by two housewives of Brookfield, Wisconsin, as a Cub Scout project with their sons. The first kits were sold at a local shopping mall and became very popular. Shrinky Dinks were soon licensed to be manufactured by the major toy companies of the time such as Milton Bradley, Colorforms, Western Publishing and Skyline Toys. The shrink plastic is still available from many retailers and can be used for a variety of things like charms and pins. The base material consists of thin, flexible polystyrene plastic sheets. Prior to heating, the plastic sheets can be colored with felt-tip pens, acrylic paint, colored pencils, etc. and cut into shapes. However, oily or waxy substances are not suitable because they melt or burn inhigh heat. When heated with the Easy-Bake Oven, a conventional oven, or a heat gun, the plastic s and becomes thicker and more rigid, while retaining the colored design. Although Shrinky Dinks are primarily an arts and crafts product marketed for children, many adult crafters and artists find the product to be suitable for jewelry making and other projects. Blank sheets are available in bulk for this purpose, and Shrinky Dinks have, rather unexpectedly, become a serious artistic medium. In 2008, University of California, Irvine Professor Michelle Khine applied Shrinky Dinks to create tiny structures for the application of microfluidics to topics such as stem cell research. In 2009, an art therapy supervision class at Emporia State University explored the use of Shrinky Dinks in art therapy. In 2014, Shrinky Dinks were presented as an art therapy medium in a workshop at the American Art Therapy Association Conference. In 2014, a team from Harvard University and MIT used Shrinky Dinks to create self-assembling robots. In 1992, the Californiarock bandSugar Ray formed with the name "Shrinky Dinx", but later changed it upon threat of lawsuit from the Milton Bradley Company.
