$ perl 892898.pl
robo_1: 1 8 28 56 70 56 28 8 1
repel1: 1 8 28 56 70 56 28 8 1
robo_2: 1 8 28 56 70 56 28 8 1
             Rate  robo_tri repel_tri    robo_2
robo_tri   2196/s        --      -42%      -93%
repel_tri  3775/s       72%        --      -88%
robo_2    31946/s     1355%      746%        --