Tools & manufacturing · c. 3,000 BCE

Lever

A rigid bar and a pivot multiply human force.

Levers moved megaliths long before writing. Egyptian New Kingdom tomb paintings show the shaduf, a counterweighted lever for lifting water. Archimedes stated the law of the lever around 250 BCE.

See it in the living tree Wikipedia Source

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

First stone tools 3.3M years ago

What it led to 3

Great Pyramid of Giza 2560 BCE
Crane 515 BCE
Screw 250 BCE