Bicycle: the whole path

1
Tools & MakingI
Stone Tools
The first cutting edge
3.3 Mya
2
Fire & ShelterI
Control of Fire
Light, heat and cooked food
1 Mya
3
Materials & ChemistryII
Pottery
Clay turned to stone by fire
18,000 years ago
needs 2
4
Materials & ChemistryII
Charcoal
Wood cooked slowly under earth
c. 4,500 BCE
needs 1, 2
5
Land TransportII
Wheel & Axle
Rolling instead of dragging
c. 3,500 BCE
needs 1
6
Materials & ChemistryIII
Bronze
Copper and tin, harder together
c. 3,300 BCE
needs 2, 3, 4
7
Materials & ChemistryIII
Iron Smelting
Wider adoption around 1200 BCE; ore, charcoal and a bloomery
c. 1,200 BCE
needs 4, 6
8
Land TransportIV
Bicycle
Two wheels driven by the legs
1817
Goal · needs 5, 7