Everyone who knows David Brewster will recall their favorite childhood toy, the kaleidoscope. But before dedicating himself to optics he studied theology at Edinburgh University and became a clergyman. But later, he took interest in physics, became a professor and then principal of his alma mater. During his experiments with light, Brewster noticed that pieces of glass, when placed into a tube with mirrors, create fancy symmetrical patterns, reflected in those mirrors. Brewster called his invention “kaleidoscope,” which means “I look at beautiful images” and patented it. Would you call it a toy? No, the kaleidoscope has been used by architects, jewelers, and decorators.