Big Bird preimage
The Big Bird preimage is a normal-looking visual image, exactly like what a person might see when looking in any direction. It is what an observer sees next to an object, shortly before Big Bird jumps out from behind it. Since the wanted criminal Big Bird was sighted in an unspecified town, the police have been advising the public to stay on the lookout for any preimage portending Big Bird's return. What this amounts to is that any prudent person, when in public, should be worrying constantly that Big Bird might be about to leap out at him.
- As long as Big Bird is not visible, obviously. It is unlikely that Big Bird will jump out from behind himself (except if the rumours of cloning are true).
- This sentence leaves ambiguous whether the detection method is for Snuffy's use or the public at large's. This linguistic limitation is part of their plot to confound the authorities.