"It felt like magic to me," says Pietro Schirano. "It scared me a little bit because it was so good."
He's talking about the latest version of ChatGPT, an artificial intelligence (AI) tool. You type something in, and it makes up a reply for you.
It's uncanny how human, friendly and intelligent the responses seem. Underneath it is an AI model called GPT-4.
Mr Schirano, design lead at business finance company Brex, has been using ChatGPT to make computer programs.
"I want to build a Pong-like game," he typed, referencing Atari's table tennis game of the 1970s. "What's the best language to [use] so that lots of people can try?"
ChatGPT not only recommended a programming language that runs in the browser (JavaScript), but also generated the code for a simple version of the game.
What would have taken an experienced developer half an hour to write took ChatGPT 40 seconds. It worked equally well for classic arcade games Breakout and Asteroids.