What does fixed in a tangible medium mean in United States Copyright?

Under the United States Copyright Act, work must be recorded in some physical medium to gain Copyright protection. The recording of a work in a physical medium is also called fixing it in a tangible medium. Â Fixation is a requirement for obtaining a copyright in the United States. Â A work is fixed in a tangible medium of expression “when its embodiment in a copy or phonorecord, by or under the authority of the author, is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration. A work consisting of sounds, images, or both, that are being transmitted, is ‘fixed’ . . . if a fixation of the work is being made simultaneously with its transmission.”

Examples of fixing a work in a tangible medium:

Writing a poem on paper;
Painting a picture on a canvas;
Recording a video of a live sports game;
Saving a file to a computer hard drive.

Examples of works that are not fixed and therefore are not granted a copyright:

The spontaneous playing of a musical instrument;
The telling of a story orally.