You can see the angle of the web and the spider in the middle.
They build their webs 3-7 feet off the ground and give them a vertical or up to 45 degree horizontal slant so they are perfect for catching flies going up and down and people walking the trails. They like the larger Diptera but they are not too excited about people. According to J. Michael Biere and George W. Uetz they orient their webs in such a way to optimize the solar radiation requirements it needs to regulate its body temperature. The female M. gracillis builds her web at sunup and when the sun goes down she eats her web leaving only the strong main lines. It is only those tightly coiled lines that are sticky and feel yucky on my face and glasses.
On the internet I read that these spiders make a stridulating sound that is said to be a low-pitched buzz and is audible to us if we are nearby. I’m not sure I believe it since I have not been able to verify the source but it is worth listening for next time I am out.