Ever wondered what that GPT in ChatGPT stood for. Yes, you guessed, its a Generative Pretrained Transformer. But what does it do and how does it work. This is the latest in a great series of videos by 3Blue1Brown produced as a video based course into the technology behind Generative AI. And it certainly seems popular. The video was only posted on YouTube two weeks ago and has already clocked up an amazing two million viewers. Not the normal kind of video to go viral!