One machine that replaced eight spinners at once.
Around 1764, the weaver James Hargreaves in Lancashire built the spinning jenny: a wheel that drove eight spindles instead of one. A single worker could now spin eight times as much yarn. Later models carried over 100 spindles. This is where industrialization starts: not with steam, but with a wooden frame in a living room.
Useful: Big upheavals often begin with a modest improvement, not the spectacular invention.
Source: en.wikipedia.org