Gears are everywhere.
Without gears, we would have to ride everywhere on horses.
Without gears, we would have to observe the sun, the moon and the stars to tell the time like the ancient people.
Gears were invented around 200 BC by someone, but it was Archimedes who wrote it down on books. Until 2013, people realised that humans weren't the only people to invent the gear, they discovered a grasshopper whose legs have gears built into them, and those gears legs help the grasshopper harness his jumping power in coordinating his legs when he jumps.
We all know that T’sai Lun （蔡伦） was the one who invented paper, but paper already existed long before he invented it. The picture here is wasps' beehive. Their nests are made of something very similar to modern paper. The wasp scrapes wood fiber from logs and other sources, and it chews into a pulp in its mouth, or it's mixed with water and saliva and then it clumps together with other pieces of nest paper. There is a rumor about T’sai Lun's source of inspiration. People said that he observed how wasps made their nest, and that inspired him to make paper.
