Seven Cambridge University undergraduates spent the summer of 2009 genetically engineering bacteria to secrete a variety of colored pigments, visible to the naked eye; they designed standardized sequences of DNA, known as BioBricks, and inserted them into E. coli bacteria — so the bacteria can now change its color to red, yellow, green, blue, brown, or violet; the bacteria can be programmed to do useful things, such as indicate whether drinking water is safe by turning red if they sense a toxin; other uses for the design bacterium include monitoring food additives, patenting issues, personalized medicine, terrorism, and new types of weather