How was the kaleidoscope invented?

David Brewster invented and patented the kaleidoscope in 1816. He described its structure and operations in a 174-page scientific paper titled Treatise on the Kaleidoscope. In his treatise, Brewster calculated that 24 fragments of glass in the object box of a kaleidoscope could create more than 1.4 x 1033 fleeting views. He also described the most effective combinations of colors for kaleidoscopes based on light properties. In the 1840s, he used two lenses to produce a three-dimensional effect in creating the stereoscope. He was also a leading advocate of the flat Fresnel lens adopted by the British for lighthouses and was credited with saving thousands of lives by protecting vessels against shipwrecks. Brewster taught at the University of Edinburgh and the University of St. Andrews in Scotland, was one of the first editors of the Encyclopedia Britannica, and published many books and scientific papers.