[svat]

The equivalent from the TeX world is `xii.tex`:

    \let~\catcode~`76~`A13~`F1~`j00~`P2jdefA71F~`7113jdefPALLF
    PA''FwPA;;FPAZZFLaLPA//71F71iPAHHFLPAzzFenPASSFthP;A$$FevP
    A@@FfPARR717273F737271P;ADDFRgniPAWW71FPATTFvePA**FstRsamP
    AGGFRruoPAqq71.72.F717271PAYY7172F727171PA??Fi*LmPA&&71jfi
    Fjfi71PAVVFjbigskipRPWGAUU71727374 75,76Fjpar71727375Djifx
    :76jelse&U76jfiPLAKK7172F71l7271PAXX71FVLnOSeL71SLRyadR@oL
    RrhC?yLRurtKFeLPFovPgaTLtReRomL;PABB71 72,73:Fjif.73.jelse
    B73:jfiXF71PU71 72,73:PWs;AMM71F71diPAJJFRdriPAQQFRsreLPAI
    I71Fo71dPA!!FRgiePBt'el@ lTLqdrYmu.Q.,Ke;vz vzLqpip.Q.,tz;
    ;Lql.IrsZ.eap,qn.i. i.eLlMaesLdRcna,;!;h htLqm.MRasZ.ilk,%
    s$;z zLqs'.ansZ.Ymi,/sx ;LYegseZRyal,@i;@ TLRlogdLrDsW,@;G
    LcYlaDLbJsW,SWXJW ree @rzchLhzsW,;WERcesInW qt.'oL.Rtrul;e
    doTsW,Wk;Rri@stW aHAHHFndZPpqar.tridgeLinZpe.LtYer.W,:jbye

Put that in a .tex file and run `pdftex` on it, then look at the resulting PDF file, which will look like this: https://shreevatsa.net/post/xii/

[fdsasd]

Yeah but that's not obfuscated, it just looks like normal TeX to me.

[svat]

There's a reason there's no IOCCC for Perl or TeX. :-)

BTW there's a 2017 followup called xii-lat.tex: https://github.com/davidcarlisle/dpctex/tree/main/xii-lat (https://mirrors.ctan.org/macros/plain/contrib/xii-lat/xii-la...) — having been done nearly 20 years later, it has even more tricks, so is more "fun" to unpack.

[nullhole]

It's like a form of especially logical compression