What constitutes a "container"?

A container by definition must be capable of holding, restraining, and containing its contents (i.e. golf tees, paper clips, and/or marbles) in the container's volume or area. Containers may have modifications as long as they meet the definition of a container and comply with the rules. While the containers do not have to be removable from the device, a key test would be the question, "if the container was moved outside of the device, would the contents remain in the container?"