So you can roll them out of the way more easily. Also - no orientation required. My physics is kind of rusty, but isn't there a strength benefit from the shap

So you can roll them out of the way more easily. Also - no orientation required. My physics is kind of rusty, but isn't there a strength benefit from the shape as well? Incidentally, many sewer covers in Australia are square, only the larger ones are round. Okay, I'm done taking this article literally now. :)