The Proper Way To Slice Your Steak

I had no idea that it really mattered but the way you slice your steak can greatly impact the tenderness according to Cook's Illustrated. In the experimenter below, these cooks determined that slicing flank steak with the grain was much tougher (193%!) than strip steak cut identically.

There's way too much science involved in achieving the proper slice for me but I appreciate those who pursue flank steak perfection on my behalf because if done correctly, a flank steak properly sliced can make be tender enough to rival premium steaks.