--- Energy ---

1. Primitive mechanical energy
- gears => mechanical energy transport
- pipes => objects transport

2. Steam energy
- steam => can be created from water/coal, can be converted
  into mechanical energy, can be stored on "steam balls"
- steam pipes => fast way to transmit pressure energy (steam)
- water pipes => transport water to create steam
- vehicles/exoskeleton
- "steam guns"

3. Electric energy
- electricity => best type of energy, can be converted into
  mechanical energy/heat/etc... Can be stored inside batteries.
- wires => very fast way to transport energy (electricity)
- everything linked to electricity (machines, crafts, vehicles, logic...)