158,962,555,217,826,360,000 (Enigma Machine)

The Nazi's Enigma Machine - and the mathematics behind it - was a crucial part of World War II.

Flaw video at: http://www.youtube.com/watch?v=V4V2bpZlqx8

Brown papers on ebay: bit.ly/brownpapers

Dr James Grime demonstrates the machine and discusses its many configurations.

James' "day job" is touring with the Enigma machine - he could even visit you - see more at http://enigma.maths.org/content/project-officer