Grey Glorious Gray

So, Megan filled me in on a little interior painting project (or rather mishap) where she attempted to paint one of the rooms in her new house grey... when she woke up in the morning the gray had actually dried baby blue!  That is a blue boo!  Anyway, she bought new paint this afternoon and as a lil bit of inspiration I wanted to show her this outfit I saw today. (via out of habit via coco+kelley) what is the difference between grey and gray??