In 1788, a meticulous British bureaucrat named John Dodd ordered a routine housekeeping task at the Palace of Westminster — the destruction of a pile of old wooden tally sticks — and accidentally set off a fire that leveled Parliament and gave us the Gothic building standing today. But the real story isn't the fire: it's what those tally sticks were, why they'd survived for 600 years, and how a medieval accounting technology outlasted the British Empire's attempts to kill it.