“My puzzle,” asked the next man, “is also about a dirigible. What’s longer, the dirigible or its perfect shadow?”
“Is that all?”
“It is.”
“Well, then. The shadow is naturally longer than the dirigible: sunrays spread fan-like, don’t they?”
“I wouldn’t say so,” another interjected. “Sun rays are parallel to each other and that being so, the dirigible and its shadow are of the same size.”
“No, they aren’t. Have a you ever seen rays spreading from behind a cloud? If you have, you have probably noticed how much they spread. The shadow of the dirigible must be considerably bigger than the dirigible itself, just as the shadow of a cloud is bigger than the cloud itself.”
“Then, why is it that people say that sun rays are parallel to each other? Sea-men, astronomers for instance.”
The professor put a stop to the argument by asking the next person to go ahead with his conundrum.
Cheers,
Nalin Pithwa
Mathematics Hothouse 