That example is a lot worse lol.

Text and audio are different mediums, their joining factor is rap.

Books and movies are different mediums, their joining factor is the telling of a story.

One kind of bike and another kind of bike are both bikes, their joining factor is that they are bikes.

If you want to use transport as an example, think of audio as a plane and text as a car. The plane cannot be compared to the car because they are used for different things. However, they are both forms of transport.

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