Once upon a time, there was a man who thought love was a maths problem. “Love is a capricious spark, a miraculous whirlwind,” one of his blog posts began, sarcastically. “It is found by following ancient prophecies, embarking on dangerous quests ... Something like that, who knows. Anyway, it sounds like finding a girlfriend was crazy hard before computers!”

The man’s name is Jacob. He is now 32 and works in finance, creating software that helps banks comply with regulations. He has dark, curly hair and a beard, a left eyebrow that’s often raised and, in his own words, a “dad bod”. His self-deprecating streak is tempered by optimism. “Growth mindset” is one of his favourite phrases. As in, “I’m still not bisexual, but, you know, growth mindset.”