Time and relative dimensions

Not quite a spoiler today, but a teaser... Over on the Royal Mythological Society site, today's topic of discussion is time travel. Which reminded me of the Roman paperweight Estelle found in the gardener's shed. I first saw these things being discussed on Time Team - yes, they are real archaeological artifacts. You don't need to know that to enjoy our fantasy explanation of them, though, coming up in the Spring book. Fans of H G Wells and Doctor Who will not be disappointed ;)