"Um. Sort of like a dome thingy, usually. The old fashioned ones are sort of pyramidy. Like this." He drew his wand and used it to draw a picture in the air. It wasn't very good, but it gave the general idea. As they walked through it, it faded away into the air. "But the wizard ones tend to be bigger on the inside, y'see. With proper beds and toilets and things. Bit pointless really. I mean you might as well stay at home, right?"