From Wikipedia:

1. Road Runner cannot harm the Coyote except by going “beep, beep”.
2. No outside force can harm the Coyote — only his own ineptitude or the failure of Acme products.
3. The Coyote could stop anytime — IF he was not a fanatic. (Repeat: “A fanatic is one who redoubles his effort when he has forgotten his aim.” —George Santayana).
4. No dialogue ever, except “beep, beep”.
5. Road Runner must stay on the road — for no other reason than that he’s a roadrunner.
6. All action must be confined to the natural environment of the two characters — the southwest American desert.
7. All tools, weapons, or mechanical conveniences must be obtained from the Acme Corporation.
8. Whenever possible, make gravity the Coyote’s greatest enemy.
9. The Coyote is always more humiliated than harmed by his failures.
10. The audience’s sympathy must remain with the Coyote.

These rules were not always followed, and in an interview years after the series was made, writer Michael Maltese said he had never heard of the “Rules”.

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