Conversation

Before 1948, someone once came up with this nice 7-word palindrome:
"A man, a plan, a canal – Panama!"

Then in 1983, someone extended it to 9 words:
"A man, a plan, a cat, a canal – Panama!"

And someone cleverer was able to extend it even further to 13 words:
"A man, a plan, a cam, a yak, a yam, a canal – Panama!"

Then in 1984 someone used Unix, a word list and a search algorithm, and it came up with this 540-word behemoth of a palindrome, which barely fits on my screen: