Horizon: How Small is the Universe? is on BBC Two at 21:00 BST on Monday 3 September. Or catch up afterwards via iPlayer (UK only).
But theoretical physicists prefer the idea that the particles are not in fact round, but tiny “strings”, like bits of elastic.
Andy Parker,Cambridge University
Above is my attempt at creating the famous Barnsley fern . It is one of the better known examples of a self-similar set, the other key example is the Sierpinski gasket.
The Barnsley fern resembles real species of Asplenium ferns, see below.
 Michael Barnsley, Fractals Everywhere, Boston, MA: Academic Press, 1993
Wikipedia entry on the Barnsley Fern
Hamish Currie had his steel toe-capped boot grabbed by a 7ft porbeagle shark after it was hauled aboard the board by the skipper. The shark caught off Islay in the Inner Hebrides.