The word "robot" was introduced to the public by the Czech interwar writer Karel Čapek in his play "R.U.R. (Rossum's Universal Robots)", published in 1920. The play begins in a factory that uses a chemical substitute for protoplasm to manufacture living, simplified people called "robots." The play does not focus in detail on the technology behind the creation of these living creatures, but in their appearance they prefigure modern ideas of androids, creatures who can be mistaken for humans. These mass-produced workers are depicted as efficient but emotionless, incapable of original thinking and indifferent to self-preservation. At issue is whether the robots are being exploited and the consequences of human dependence upon commodified labor (especially after a number of specially-formulated robots achieve self-awareness and incite robots all around the world to rise up against the humans).