
IT'S ALL ABOUT DIRECTION!
The direction that the grass is bent determines the "light" or "dark" coloured stripe. When the blades of grass are bent away from you, the grass appears lighter in colour because the light is reflecting off of the wide, lengthy part of the blade. When the blades of grass are bent towards you, the grass appears darker as you are looking more at the tips of the blades, a smaller reflective surface. So cutting a lawn in an opposing pattern (up/down, right/left, etc) provides the most contrasting stripe effect. Interestingly, as the "colour" of the stripe is dependant upon what direction you are looking at it from, a "light" coloured stripe will appear "dark" if you view it from the opposing direction.
