The loop in &guessing is not really a loop at all. It will either exit (bad form to exit from a subroutine) or execute the last statement on the first pass. I think that while really wants to be an if.

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print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';
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