This summer, my friend and then co-worker, Holly Sutherland and I would take walking breaks during the day to get in our miles for the #500in2014 challenge and also have informal (but informative) PD chats while we walked. Our school is so large that from our offices to one of the ends of the building on the same floor is about a quarter of mile. We got in some good mileage in those days! On one of those walks, I shared with Holly that I wanted to write a blog post about classroom spaces…