Like this? 
my $c = 0;
$_ = "jigglewort\n";
print and $c++ while s/(.{$c})(.)(.)/$1$3$2/;

[download]
producing: 
ijgglewort
igjglewort
iggjlewort
iggljewort
igglejwort
igglewjort
igglewojrt
iggleworjt
igglewortj

[download]

In reply to Re: YET another regexp puzzle by Anonymous Monk
in thread YET another regexp puzzle by carric

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