In 1986 the "right" to have large signs in Lafayette Park
disappeared when the government enacted the "sign size"
regulation, again written by Richard Robbins, limiting signs,
again for "aesthetic" concerns, to no larger than four foot
square, and requiring that they be attended "within three feet."
Vigilers have suffered assault and imprisonment under this rule.
Based again on the precedents set in Clark v. Community for
Creative Non-Violence and Equal Rights Amendment v. Clark, the
Court of Appeals justified sending Carl Musser to four months in
prison because he briefly strayed more than three (but less than
ten) feet away from two signs. 
Still, the vigil has managed to endure. But this is where the
"three cubic feet" regulation comes in.
The Lafayette Park
"Sign Size" Regulation
 United States v. Musser, 872 F.2d 1513 (1988). ]
3-CUBIC FOOT RULE