I just realized while washing dishes that the The Twilight Zone (1959–64) theme is also the Night Gallery (1969–73) theme, only the rhythm is different. Not only that, but the same music also appears in the great Night Gallery pilot episode (the one with the awesomely scary episode feature Roddy McDowall and the other with evil bitch Joan Crawford which was also Steven Spielberg’s first directing job).
All three themes sound completely different at first hearing, due to tempo and tone color. But they are all one and the same melody.
FACT CHECK: I am the first person to say this on the Internet. This, finally, is my unique contribution to RTF studies.