Imagine that you are managing a construction site. Your staff has all the rebars in their places and concreting is about to begin. Then you hear that you are short on rebar stirrups, rebar stakes or 90-degree hooks. All you have available on-site are straight rebars.
This situation is very common in concrete construction projects. This does not mean that you cease all work and operations. You can always bend rebars on-site using various methods.