ELON MUSK: "Optimus will be the biggest product ever, but it is a very complex problem to solve. It's one of the hardest things to solve, to make an autonomous humanoid robot that can do tasks that, if you simply ask it to do something or show it a video, it can do the task without any programming.

No one's ever achieved this, and there are many challenges in the design of the robot to achieve sufficient dexterity and to be very reliable and have long wear and tear, meaning it needs to be out in the field and not break down.

Otherwise, you've got sort of a 70 kilogram robot that just flopped over and you've got to carry it out like a body, you know, it doesn't have wheels. And we don't want Optimus to go haywire. So it's a lot of work to scale, to get the design right and to scale production. This is going to be the hardest product to scale manufacturing that we've ever made at Tesla because everything on the robot is new. And the difficulty of scaling the production ramp is proportionate to the newness of the parts in the robot.

With Optimus, there is no supply chain. So we've had to build up a supply chain in its entirety or in-house the production. The Optimus production line that we're building out in Fremont in place of what used to be the Model S & X production, it looks incredible. It's quite stunning to see."