Anticipating the success of a product is not an easy task. Human history is full of both successful and unsuccessful products. Although simple toys like the hula-hoop were a tremendous success, the swing-wing--a toy based on similar concepts--was not successful at all.

The Swing Wing was a toy designed to capitalize on the fun of moving your neck back and forth repeatedly. It was a big failure in terms of adoption, despite its similarities to the extremely successful, waist-moving hula-hoop (the preceding image was found from https://en.wikipedia.org/wiki/Swing_Wing_(toy), https://archive.org/details/swing_wing).

Every app starts from an idea, and you never know for sure if that idea will work in practice. Waiting until your product gets built in order to validate your idea represents a big risk--if things don't go as expected, you'll have little room to change course. It would be more useful to know how users will react to your product much earlier.

Fortunately, you can evaluate your ideas earlier, thanks to prototyping. A prototype is a simulation of relevant parts of your solution that allows you to learn from your users before building the real product. In this way, you don't need to wait until your product is completed to check whether your idea works as expected. Prototyping will save you time and help you deliver a better product that is more likely to solve the real needs of your users.

Building prototypes is fast, but it requires you to understand the purpose of prototyping, pick the right tools, and plan the process. This chapter will provide guidance through those aspects so that you can bring your ideas to life as soon as possible.