A man on stilts is playing a tuba for money on the boardwalk .
It is certain that a man on stilts is playing a tuba while guggling something on the boardwalk .
It is impossible that a man on stilts is playing a tuba while guggling something on the boardwalk .
It is certain that a man on stilts is playing a tuba while guggling something on the boardwalk .
A man on stilts is playing a tuba while guggling something on the boardwalk .