Hard at Work

This little spider is building a giant web that starts way up in the branches of a very tall beech tree and ends on the deck railing. It looks like the spider was weaving with both front and back legs simultaneously, but I don't know if that is possible. 
When I got close to take a photo, the spider ran up the web. After a few minutes, it came back down and I was able to take a blip.
My granddaughter spotted the web and spider and was fascinated with it.