my $one_two_threes = seq( 1 .. 3 ); enumerate( seq_prod2( $abcees, $one_two_threes ) ); # 0 => a 1 # 1 => a 2 # 2 => a 3 # 3 => b 1 # 4 => b 2 # 5 => b 3 # 6 => c 1 # 7 => c 2 # 8 => c 3