Chuck Jones, the rules for "Road Runner"

The Road Runner cannot harm or upset the Coyote except by going "Beep! Beep!"
No outside force can harm the Coyote only his own ineptitude or failure of Acme products.
The Coyote could stop anytime if he were not a fanatic.
No dialogue ever except "Beep! Beep!"
The road runner must stay on the road otherwise logically he would not be called the Road Runner.
All action must be confined to the natural environment of the two characters - the Southwest American desert.
All materials, tools, weapons or mechanical conveniences  must be obtained from Acme corporation.
Whenever possible, make gravity the coyote's greatest enemy.
The coyote is always more humiliated than harmed by his failure.