A prototype that works like the proposed solution, with all the key functions, but not necessarily in the final form along with experimental data documenting the performance

The need for prototypes that demonstrates the key functions of the proposed solution is pretty well understood. They are needed to demonstrate that the product design is reliable, reproducible and is capable of being manufactured at a cost that will support the defined market needs and price point.

The Works Like prototypes need to show that the major risk areas of the product design are defined, and the key functions of the anticipated solution can work. Completion of feasibility typically entails the construction of a partial or full working prototype device that is capable of performing as specified and demonstrates that the major risks have been overcome. The prototype fulfills either the intended use or the critical risk components of the intended use. Failure modes will be defined and exercised, and a preliminary bill of materials backed up by supplier quotes on key components is developed.