Groundskeepers Display Artistry on the Diamond, September 30 (?) New York Times. David Mellor, the current head groundskeeper at Fenway Park, is the one who started the trend of mowing the grass in such a way as to create interesting-looking patterns; apparently he first did it in order to camouflage some damaged grass in Milwaukee in the early 90s. Roughly speaking, the mowing action bends the grass in one direction or another, creating contrasts of light and dark; you can see a similar effect when you vacuum your carpet. (I really mean "you" here. I can't; I have wood floors.)
And we're told that "High-school geometry classes visit [Mellor] at Fenway Park to study ways that an odd-shaped field can be divided and subdivided by straight lines and sharp angles."