use strict;
use warnings;
use Data::Dumper;

my @ary = (
   [1, 2, 3],
   [4, 5, 6],
   [7, 8, 9],
);

my @col = map splice(@$_,0,1), @ary;

print Dumper \@ary, \@col;
[download]

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)

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