When I bought my little girl Marcia the small clear backpack, it was because I’d been sold on its two main advantages: Getting Marcia through her school’s security as quickly as possible, and keeping things organised. Marcia’s smart, but she’s a dreamer. She’s a dreamer now and in constant need of reminders about everything – I can’t wait to see what she’s like when she’s seventeen and actually has things to worry about! Part of Marcia’s dreaminess plays out in a pretty rich imagination. Marcia can spend days on end pretending one thing or another. She once pretended to be…