Silicon Valley is in a bitter standoff over three rods and seven discs. And while the fight involves a brain-teaser available in most toy stores, the stakes are high. It threatens billions of dollars in capital expenditure and the future of everything we know to be true.

The Tower of Hanoi is a classic maths game used to test reasoning, where players have to transport a stack of discs from one rod to another without stacking a bigger disc on a smaller one.