Inside a concrete block at the top of a hill in San Francisco, 27 nine-year-olds are handed needles and ordered to sew. Across the hall, eight-year-olds churn butter by hand, while downstairs four-year-olds are busy carrying out their duties: sweeping up, washing dishes and dehydrating fruit.

This is not a child-labour camp in the heart of America’s richest city. It is a school, and among the tech crowd it has become much sought after. The San Francisco Waldorf School, you see, has a strict “no screens” policy. In fact, it is deliberately “analogue”, a throwback to a time when it was all blackboards, pencils and paper — but with a new-age twist. And in the crucible of the global technology industry, the same executives