 So after we have discussed architectural styles we'll now continue and go into something else called application architectures or generic application architectures. The main idea here is that you have common architectures, common software architectures that work as long as your business is actually similar. So if you are a company that processes data heavily you might use a similar architecture to other companies that do that, for example. And a typical example are ERP systems, enterprise resource planning systems, large systems that are very easy to tailor to different business contexts, but they all have very similar characteristics. For example they need to be able to handle invoices that need to be able to handle staff and so on. So the architecture is very common for those and there are companies that earn a lot of money just by essentially tailoring their application to specific contexts. For example companies like SAP or Oracle have their main business in this area. So that's an example, but common ways or common architectures are for example data processing applications. So applications that have to process large amounts of data. You can look at that if you are in such a use case. Transaction processing, so you have some kind of transactions like financial transactions that you need to deal with. Event processing applications, so large events, large amounts of events from users, for example, and language processing. And there are some examples for these in the book, so I won't go into much detail, but essentially what you can do is try to figure out is our business, is our product in any of these areas and if yes you can just look at examples of how do they do this, how do they do transaction processing, for example, and use it in a way as a design checklist. Could we do similar things, use it as a way to maybe reuse components, maybe there are already components in that area that you can buy or that are even for free. So and in a way have a checklist as a best practice whether you're doing similar things. And the way this is done in the book is that they simply give you some examples of how different styles could be used. For example, transaction processing, there is an example of an ATM, automatic tele-machine to withdraw money. And this could be organized, for instance, using a layered architecture. So you just have the different layers from the user actually pressing in the pin and requesting how much money he or she would like to withdraw to the actual processing, sending it to the bank, but also returning the money and so on. So it's just different ways that are sort of fitting a specific business context. So this is in contrast to the styles where we had solutions and we basically knew that this solution is good for performance, this solution is good for security. Here it's more this solution, this architecture is good, is suited for a specific business. So it's a different concern in a way. So this is all we'll do on the common or the generic application architecture. So I just wanted to mention this and now we'll dive into a slightly different area of architecture.