Since low-fidelity prototypes are cheap, both in terms of money and time, you can afford to have more cycles of testing, more subjects, or more prototypes. Getting the prototype ready The classic example of low-fidelity prototyping is using paper and pencil to mockup interface screens. These can be as simple as hand-drawn boxes with scribbled controls, or drawings done in a computer drawing program and printed out. Make one of each screen in the interface. Also, make paper representations of menus, button groups, scroll bars, and the like.
Some people use transparancies for layering elements on top of one another.
I think that's too much trouble. Transparancies are a bit messier and harder to work with during the evaluation. Low-Fidelity Prototyping in action Now comes time to use the prototype in an evaluation session. For example, in an informal thinking-aloud protocol usability test, you could use two evaluators, one to run the test, and one to manipulate the prototype. Sometimes the action can get pretty hectic, especially if you have one of those expert users that loves to click everywhere.