This reading introduces the method of creating a physical prototype for any physical design. Use of basic cheap materials by designers to create these physical mock-ups such us foam core, cardboard, glue, scissors, paper, and cutting knife has been focused. Tracing a photo to create an arm sketch on the computer is a starting step to provide an example of a digital watch. After the sketch is printed and placed on the foam with the right size. They cut the screen and place a paper prototype for a series of screens that are going inside the arm and appears in the cutter foam screen , after preparing the arm. This way the designer is testing the steps performed on the digital watch using a physical prototype. I will say, this method is easy to implement and design. It is also cheap and does not require an designing skills or special materials. The designer can start building his/her prototype at home using basic material. However, I think printing the prototype screens is better than drawing the sketches. The physical mock-up can be created directly after the sketching stage or even within the sketch stage to save time an effort of duplicating the work of prototyping.