Ladder e railway semaphore: o que têm em comum

1. Passo 1. Ladder — utiliza — Inclined plane. Climbing to a height.
2. Passo 2. Inclined plane — é utilizado em — Egyptian pyramid. According to a common hypothesis, the blocks were raised on ramps.
3. Passo 3. Egyptian pyramid — utiliza — Lever. Levers were used to move the blocks.
4. Passo 4. Lever — é utilizado em — Railway semaphore. The semaphore is set by a lever.

Abrir Evothings