When a person uses another person's intellectual property in a way that diminishes its value, that action is called infringement. Infringement can involve patents, copyrights or trademarks.
Utility patents generally cover how products work, are used or are made. Those who own patents can stop others from using their products or products' functions for up to 20 years after the filing of the patent. Design patents last only 14 years. These protect what a product looks like.
Copying the person's product isn't the only way that another person can infringe on the patent. For instance, creating a sufficiently similar invention or incorporating the invention into a new product or business may be enough to constitute infringement. It typically does not matter if the violation is intentional or not.
With copyrights, infringement is typically intentional. People take the copyrighted item and use it exactly as is, either by using a portion of the item or the item as a whole. It's almost impossible to use an image or product in that manner without knowing that the law is being broken. For instance, if someone takes another person's artwork and places it exactly as-is on a T-shirt, that's a violation of the individual's copywritten design.
With trademarks, the marks show a brand or are related to a brand. For example, "Just Do It" is specifically used by Nike with the check-like symbol. If someone uses a mark similar or takes the phrase and uses it on their own products, that would be a violation of Nike's trademark.
If your property has been infringed upon, know your rights. The right help can stop others from using your property.
Source: FindLaw, "Avoiding Infringement Problems," accessed Nov. 17, 2017