Noble's life

A castle

Including 4 walls
- Visual: 4 sprites
- Physical: 4 Mountain lines
  - Re-use built-ins mountain...
Castle total health: the main base health, only collapse base health meaning
- Composite structure
Castle gate health
- The isolated part of the gate, if the gate health is downn the gate no longer close
- The defenders can repair the castle
Attackers with range weapon cannot shoot people under the castle wall
Saving and loading castle sprites and tile system
Closing gate by placing the mountain tile at the front of the gate

Each City only have 1 castle if meet the required condition
- hook into game event
City buil-in defend mechanic, when regconize enemeies on the border of the city there will be evaluation for the commander of that army to raise alarm or not