Similar to the Korean bath room state machine, this is a Japanese ramen booth seating chart state machine. It shows how many and which seats are empty.
This water kettle that my mom bought can boil water and also keep the water warm. When the light is red, it means the water is heating, and keep warm is not on. When the light is purple, it means the water is heating and water well be kept warm once it finished boiling. When the light is blue, it means the water is being kept warm.
