This clip explains the legal definition of a trade mark, the reason trademarks are protected by law, and a brief example of when trademarks are useful.

This clip explains what rules something must abide by in order to obtain trademark protection, and lists the numerous things (sounds, logos, names, etc.) that can be trademarked. Stan also gives an example of how some things, such as flavor, cannot be trademarked, and why that is the case.