In this case they all refer to building the same thing, but at different steps in the process. Theoretically each step could be carried out by a different perso

In this case they all refer to building the same thing, but at different steps in the process. Theoretically each step could be carried out by a different person, but in modern practice it would be quite unusual to do so – which is why they can be, and are, used interchangeably. If someone is doing one of them it is almost certain they are doing all of them.