Surreal numbers are created by adding values between two given preexisting numbers. If you look at 0 and 1, for example, 1 / 2 is in the middle, 1 / 4 is between 0 and 1 / 2, and so on.

It can take years to learn how to write computer code well. SourceAI, a Paris startup, thinks programming shouldn’t be such a big deal. The company is fine-tuning a tool that uses artificial ...