Andrej Karpathy, the former director of AI at Tesla, has returned to OpenAI. He was one of the founding members of the company, but left in 2017 to join Tesla and work on AI projects with Elon Musk. 

While at Tesla, Karpathy worked on various AI initiatives, including the development of the humanoid robot 'Optimus' and leading the computer vision team for Tesla Autopilot. However, in July 2022, he left Tesla without any specific plans. In October of that year, Karpathy appeared on Lex Fridman's podcast and praised Tesla and Elon Musk, expressing his desire to potentially return at some point. 

Following his time at Tesla, Karpathy has been actively contributing to the open-source community and has created courses on building deep neural networks. He has also released an updated version of minGPT, NanoGPT, a fast repository for training and tuning medium-sized GPTs.

Karpathy holds a PhD in computer science from Stanford University, specialising in deep learning and computer vision. He has used his expertise to create educational content, including videos on neural networks and language modelling. These videos are accessible through Jupyter notebooks and come in two categories: a basic introduction to neural networks and backpropagation and a more advanced lecture on language modelling. 

Karpathy's focus on open-source and education aligns with the mission of OpenAI, which makes it a natural fit for him to return to the company.

It is exciting to see Karpathy return to OpenAI, where he can continue to contribute to the advancement of AI technology. With his expertise in deep learning and computer vision, he will no doubt play a critical role in driving forward the company's research and development efforts. The developments in AI are inspiring and having experienced them first-hand, Karpathy is eager to jump back in and build. It is a testament to his passion for AI and his dedication to advancing the field that he has returned to OpenAI to continue his work.