A mermaid silhouette can have a mystical quality. The fact that they lack so much detail forces you to use your imagination. You are invited to the world of dreams where myths are made. Joseph Campbell said that "A myth is a public dream, a dream is a private myth". These simple shapes ask you to project your own dreams onto them.
In eastern meditation you often use some object as a focus for the meditation. This is something I often do myself. You select an image or a memory and focus your attention on it and nothing else. You imagine or remember it in as much detail as you can. Psychologists also use this technique. It is a type of self-hypnosis and is often used to control fears and phobias.
Eveyone has my permission to use any of these silhouettes in craft projects or as avatars without contacting me.
Neither is permission necessary for use in meditation.