local $";
while (<DATA>) {
    s/(\w{4,})/@l=split'',$1;@m=@l[1..$#l-1];@r=map{splice@m,rand @m,1
+}@m;"$l[0]@r$l[-1]"/ge;
    print;
}

__DATA__
Down that path lies madness. On the other hand, the road to hell is pa
+ved with melting snowballs.
Although the Perl Slogan is There's More Than One Way to Do It, I hesi
+tate to make 10 ways to do something.
And don't tell me there isn't one bit of difference between null and s
+pace, because that's exactly how much difference there is.
Randal said it would be tough to do in sed. He didn't say he didn't un
+derstand sed. Randal understands sed quite well. Which is why he uses
+ Perl.
As usual, I'm overstating the case to knock a few neurons loose, but t
+he truth is usually somewhere in the muddle, uh, middle.
Of course, I reserve the right to make wholly stupid changes to Perl i
+f I think they improve the language.
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