The same general construction could be added to to change the function of a truck.
A tip truck. This truck can carry sand, gravel, soil, bark and other materials, dumping them right where they are needed.
This truck has fold down sides that enable easy loading and when up keep the load safe when traveling.
This truck has a crane that enables the drive to load and unload heavy loads.
The tank on the back of this truck enable the driver to deliver liquids to sites.
The canvas covers on the back of this truck protect the cargo when traveling while making it easier to unload at it destination.
The solid back cargo container keeps goods protected while being transported.
The fully enclosed refrigerated cabin on the back of this truck enables the driver to deliver frozen goods to supermarkets.