The machine was born in a sandbox. Stumbling for meaning, its five parents watched as it learned the rules of the world around it. Everything is built of cubes, which can be climbed one at a time. There is light, and there is darkness. “Up” has a meaning different from “down.” The machine learned. The makers gave the machine a task: go up. And, eventually, the machine did just that, safely within the confines of its Minecraft world. Microsoft, which owns the wildly popular open-ended game, is using the setting as a laboratory for artificial intelligence. This summer, they’re opening it up for everyone.