The pieces are the main building blocks for the pages. Technically speaking you can refer to these as ‘sections’, combinations of global elements that form recognisable - and more likely reusable style blocks.
As the MPS method is about efficiency and DRY (Don’t Repeat Yourself) it’s important when designing pieces to choose pieces that are (in some sort form) being used globally trough the project - or are pieces that are used once but have a certain importance e.g. the header, footer, an article (in various view modes) and so on, this mainly depends on the project.
When the previous step (defining ‘Principles’) is being done right, the designing of pieces should be a piece of cake. We can use font-sizes, colours and buttons easily and focus ourselves completely on designing the layout.
The pieces that are created can be presented just as you would present a mock-up or page design. Put them beneath each-other starting with the header(s), navigation, UPS’s and then the other pieces by importance - this will give the client a good view on how the pieces will look like (on a page).
After reviewing and modifications we can start the next step of this phase - creating Pages (better known as mock-ups).