Tesla boss Elon Musk presents humanoid robot Optimus

Tech billionaire Elon Musk has presented the latest prototype of a humanoid robot being developed by his Tesla electric car company. Optimus appeared on stage at a Silicon Valley event, where it waved to the audience and raised its knees. The CEO said the robot was work-in-progress but could be on sale to the public in a few years' time. Tesla's mass-market robots will be tested by working jobs in the car factories, company engineers say. The prototype was wheeled on stage during an annual Tesla AI [artificial intelligence] Day presentation.