[PRL] Palindromic programs

[Doug Orleans]

This morning I wondered what the longest (ignoring whitespace)
palindromic Racket program was.  Obviously any palindromic integer is
a program, but that's not too interesting.  There's also "(quote
etouq)" but I couldn't think of a good way to extend that.  Then I
came up with this:

(letrec ((letrec letrec) (certel certel)) certel)

This can be extended indefinitely:

(letrec ((letrec letrec) (gateman stressed) (nametag desserts)
(stressed gateman) (desserts nametag) (certel certel)) certel)

These just return #<undefined>, though.  Is there a palindromic
program that actually does something interesting?

--Doug

P.S. Here's a palindromic quine in C:
http://www.derf.net/palindromes/old.palindrome.html#CODE