Catching a Moth

As I was heading into work today I looked to the left of the door and saw something unusual.

 Since I had my camera with me, I had to take a picture.  The only problem was that I couldn't identify this particular moth.

 I think it may be a porcelain gray based on a website, but I'm not sure.  The colors don't look quite right.  Apparently they vary in color and the patter looks about right.  NOTE:  After posting one of these pictures on a facebook group, apparently it's a maple span worm.

I just wish I could have gotten a more frontal shot.