Code Palindromes

An idle thought on a long weekend. Is it possible to create an executable binary which is a palindrome?

It's trivial to create a palindromic program in, say, Python:

 Python 3print("hello") # )"olleh"(tnirp

Save that as test.py and then run cat test.py | rev | python3 and it'll work. But that's boring!

You could do the same by reversing the bits, rather than the characters:

 YAML01110000 01110010 01101001 01101110 

01110100 00101000 00100010 01101000 

01100101 01101100 01101100 01101111 

00100010 00101001 00100000 00100011 

00000100 10010100 01000100 11110110 

00110110 00110110 10100110 00010110 

01000100 00010100 00101110 01110110 

10010110 01001110 00001110

That requires a bit more bit-bashing to run properly. And, if I'm honest, I think padding stuff with reversed comments is cheating.

Is it possible to make an executable assembly program which can be read forwards and back?

Alex @regularfry@mastodon.social Young

@regularfry

Replying to @edent@edent Related question: are there any paper tape programs which are valid when taped end-to-end as a mobius loop?

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