use strict; use warnings; use Data::Dump qw(pp); my @f; for my $i (0..40) { my @e=($i+=2, $i+1); #same as ($i+2, $i+3) push(@f,\@e); } pp \@f; __END__ Not sure if this is what you want, but this code results in: [ [2, 3], [3, 4], [4, 5], [5, 6], [6, 7], [7, 8], [8, 9], [9, 10], [10, 11], [11, 12], [12, 13], [13, 14], [14, 15], [15, 16], [16, 17], [17, 18], [18, 19], [19, 20], [20, 21], [21, 22], [22, 23], [23, 24], [24, 25], [25, 26], [26, 27], [27, 28], [28, 29], [29, 30], [30, 31], [31, 32], [32, 33], [33, 34], [34, 35], [35, 36], [36, 37], [37, 38], [38, 39], [39, 40], [40, 41], [41, 42], [42, 43], ]