They make our cars, and some clean our floors. Bill Gates even thinks that we should tax them. Now robots are moving into a brave new world: the stage. The humanoid RoboThespian has taken to the boards in London, acting alongside humans. Co-star in a play called Spillikin, he can wave his hands around, make faces, talk and blink. But RoboThespian is not quite autonomous. His performance is activated by nearly 400 separate, preprogrammed triggers. ”The robot will always say the same thing and move in the same way depending on what cue is being triggered at what particular time,” said the play’s writer and director, Jon Welch. That can put a lot of pressure on the human actor “to always have the right lines, always stand in the right place so that the robot is looking at the right direction at that particular moment,” Welch said. In the play, a designer of robots builds a companion shortly before his death for his wife, who has Alzheimer’s. Spillikin, at the Pleasance Theatre until March 19, is billed as “the oddest of odd-couple romances.” Judy Norman, who stars alongside RoboThespian, holds his hand, talks to him and, at one point, kisses him. “When he looks at me, this going to sound weird, but he is very affectionate,” she said. “And I like him, I really like him.”