During an engineering interview, you may be asked to explain how a particular product is made. This type of question tests a candidate's manufacturing knowledge, as well as your ability to communicate the steps required in the process. In the case of LEGOs, they are a well-known example of the manufacturing process known as injection molding. This involves starting with stock of plastic material in pellet form, then using high pressure and temperature to melt and inject it into a mold. Once the plastic part is formed inside the mold cavity, cylindrical rods known as ejector pins are used to knock it out, where it cools until it is ready for use.