use strict;

my @array = (13, 27, 4, 18, 12, 6);
my %hash;
@hash{@array} = (0..$#array);
my $index = $hash{18};

print "should be 18: ", $array[$index], "\n";
print "should be 4: ", $array[$index-1], "\n";
print "should be 12: ", $array[$index+1], "\n";
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jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)