I recently read this book to my 6 year old class. After they insisted I read it again, I handed them each a paper with a box drawn in the middle. "This is your Not-A-Box. Now you must draw what you see when you look at this Not-A-Box."
They drew trains, castle towers, houses, semi-trucks, and on and on. It opened their imaginations up. Later some of the parents told me their children had asked them to purchase the book.
My own 6 year old daughter reads this book to her siblings frequently. Who knew that such a simple story with simple drawings would have such an appeal?