A storage tank has a container to keep a certain amount of fuel and it also has an indicator to inform about the level of fuel inside the container.

The container cannot exceed the maximum capacity of the tank and the indicator is represented by a light with states on and off. Also the indicator reads the level of fuel inside the tank and it signals when the level has reached the maximum by switching to state 'off', that is it is on during the fill operation. Assume the maximum capacity of the tank to be 5000 and the indicator to signal a danger level when capacity of the tank reaches 50.

(a) Write a valid schema for the container.

(b) Write a valid schema for the indicator.

(c) Write a schema for the storage tank by combining both of the above schemas.

(d) Write a schema for the fill operation.

(e) Write a schema to represent the state when the tank is overfilled.