From Brilliant Knitwit's Tumblr, an optical illusion TARDIS scarf, knitted as a gift. From the front, it just appears to be a striped scarf; at the right angle, the hidden TARDIS heaves into view.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.