There are three main purposes we built prototypes, to answer questions. To communicate, and to serve as milestones in the design process. So let me just take those in turn. First of all, to answer questions. There are usually two main questions that you're trying to answer in design. The first question is a question about the solution. It's basically, will it work? And the second is a question about the need. And that is really, will the users like it? Is the need real and will users like it? And in a commercial setting, those questions are basically the solution or technology risk and the market or the user risk. They address those two kinds of risks. So, you're trying to answer the question, will it work? And you're trying to answer the question, will they like it? So, just to give you a, a few, Few examples of that. So if we go back to the bike seat example, this prototype which I considered a proof of concept prototype, Answer the basic question of, will it work? Does the concept, as articulated or as envisioned, actually deliver on the need? Another kind of wheel at work question is the one that I addressed with these prototypes, which is basically the question of which of these different saddle shapes is the most comfortable? And so prototypes are often used to answer those kinds of questions as well, which are fundamentally solution questions. Questions about the form of the solution. The other kind of question though, is the will they buy it question, or will they like it question. And, that was the question that we addressed with this alpha prototype, which, I made ten, I gave them out to a bunch of friends. I asked them to try it, and to report back. And, basically I looked for, who gave it back, who never tried it, who refused to give it back, as an indicator of, did they really like it, did it address their, their need. There's a model in marketing called the ideal point model which posits that every user has in a conceptual space a possible attributes for the artifact an ideal point. That is, the point they are maximally satisfied at which the gap is closed. And so, one way to think about what you're doing in design is you proceed through the design processes. You've got a point in the attribute space or the conceptual design space that's, That really does address the users' need, that is, that is their ideal point. But you also have what they said their ideal point was. That is, their needs as articulated by them. And then you have, and it's often different from those other two, the needs as you heard them. As, as designer, that is what you understood the users' needs to be. And then furthermore, there's the question of what you actually delivered. What is, what, to what extent does the artifact that you actually delivered meet the needs that you thought it would? And, every one of those is a little bit different, and so, what a prototype does is it compares the users' actual needs with what it is that your artifact delivers in the form of a prototype. And you can sense that gap using the prototype and identify whether in fact, you've solved the problem or closed the gap that you set out to solve. So that's the whole first category of motive for prototypes. We use prototypes to answer questions. The questions are of two basic forms. Will it work and do they like it? Will it close the gap? The second reason we build prototypes is to communicate. Let me tell you a little story about that. Two summers ago, I was nominated by members of my extended family, to design a bunk house for a rustic cabin site that we have, we've had in our family for many decades. And, we needed more space, and, it's a, a large, it's a large group of stakeholders, maybe 30 or 40 people who use this land. And so, I set out to try to understand the user needs before designing this bunkhouse. And one of the things that I did was to build an analytical prototype using Google Sketch-up, that articulated one vision for what that, what I heard the user needs to be. And so I'm showing you here, the Google Sketch-up model of my first concept of what the bunkhouse would look like. And in fact, they even put the model into a photograph of the actual site. And standing here on the deck is my brother-in-law, Brett, who, That's his actual photo, and he's often standing on the deck at our cabin and so I put him on there, and I gave everyone, I sent this image around, to the extended community, and said, what do you think? And the goal of this analytical prototype was to communicate, was to say, hey, this is the design we're actually thinking about, this isn't just words anymore, this is what we're envisioning, what do you think? And I learned that basically, I'd gotten the vision roughly right, but they said two things. One thing they said was, you know, we really would like some doors on that bunk house. It's a little too open, a little too rustic now, it'd be nice to if we could shut it up and close it up to the weather, and if we did that, we could eliminate that door on the side, so that, so that you could put, get, have all of the in grass and egress access to the cabin, through the front, through some swinging doors. They also said that they didn't like the siding material. And they really hoped that we could do it in cedar shingles like the main cabin. So I made some revisions to the analytical prototype. I, shown here, I sent those around and everyone said yeah, that's it. And, and so we went and built the, the bunkhouse. And, and it worked out extremely well. Everyone likes it quite a lot. We ended up making one further change on site after we'd tried it out for one season, which was to add a second level of deck which everyone really immediately recognized they wanted as a way to avoid having a rail on the front that would obscure the view. So, that's an example of how prototypes are used to communicate. A prototype can be a very powerful mechanism for bringing together a large group of users or a management team or group of investors or an extended group of stakeholders, to get them aligned with what you're doing as a designer. The third motive for building prototypes is, As use is, for use as milestones. Now most of you have heard of a beta prototype. You know, Google is famously known for, for identifying their products as beta or in beta even well into their into, well into their adoption. Sometimes, I believe Google Gmail was considered in beta even after it had ten of millions of users. That word is an example of a, It's a label that's used on prototypes that are used as milestones. The typical labels used on a prototype are proof of concept, prototype, alpha prototype, beta prototype and pre-production prototype. Those are typical labels used. And often as consumers we just hear beta because beta is the first version that's typically made public or shown to a large group of users. Those particular prototypes are almost always comprehensive prototypes. That is they're complete prototypes that have all of the features and functionality typically. That is at least beta does. And they're remarkably effective at bringing together a large team around the completion of a design. They serve as tangible reminders of where you are in the process. They're very hard to fake or to bluff because the prototype either works or it doesn't. They're very visible. They're very tangible. They get everyone excited. And so those alpha, beta, pre-production. Prototypes serve as quite effective milestones in managing a project, towards getting the completion of the design of an artifact. So in sum, prototypes are used for three main purposes. Answering questions, those questions are of the form, will it work, and will the users like, and second motive is communication to the extended group of stakeholders. And the third is to serve as a milestone in the management of a project to get a design completed.