I am using a lof of "Throw-away Software Prototype"."Throw-away Software Prototype" is a piece of software application which is not well engineered. It is not gone in a formal process for software development. It will be destroy after the initial stage of software life cycle.

I used this kind of software prototype to evaluate whether the requirements is possible to be implemented and verify whether my design is workable.

But there is very very important point, Don't try to improve the prototype and put that into a production. This is very high risk, because this type of prototype is not well design and analyzed. We don't know whether there are any hiding defects and design fault inside.