evidence: Elon Musk said Thursday night at Tesla’s AI Day that the company is building a humanoid robot, and will probably have a prototype next year. [...] Musk described the robot as an extension of Tesla’s work to build self-driving vehicles. The robot will use the same computer chip, and navigate with eight cameras, no different than Tesla’s vehicles. [...] Musk said at AI Day that Tesla wanted to show it’s more than an electric car company. Several of his employees gave presentations touting Tesla’s expertise in artificial intelligence, which is critical for developing self-driving cars or a humanoid robot.