Color reflected color depends upon the viewing angle. Numerous scientists have carried out research in butterfly wings and beetle shells, including Isaac Newton and Robert Hooke. Since 1942, electron micrography has been used, advancing the development of products that exploit structural color, such as "photonic" cosmetics. Color Color (American English), or colour (Commonwealth English), is the characteristic of human visual perception described through color "categories", with names such as red, orange, yellow, green, blue, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the visible spectrum. Color categories and
Colour revolution groups, even borrowing the colour orange from the Ukrainian revolution. In November 2005 protesters took to the streets, waving orange flags and banners, to protest what they considered government fraud in recent parliamentary elections. The Azerbaijani colour revolution finally fizzled out with the police riot on 26 November, during which dozens of protesters were injured and perhaps hundreds teargassed and sprayed with water cannons. On February 5, 2013, protests began in Shahbag and later spread to other parts of Bangladesh following demands for capital punishment for Abdul Quader Mollah, who had been sentenced to life imprisonment, and for others convicted