I learned something today.
Semaphore Flag Alphabet: Denelson83 http://commons.wikimedia.org/wiki/File:Semaphore_Alpha.svg
'N' is for Nuclear
'D' is for Disarmament
Put them together and what do you have?
Peace symbol by: By Symbol: Gerald Holtom; file: Crotalus horridus - Originally uploaded to en.wikipedia as Image:Peace Sign.svg., Public Domain, https://commons.wikimedia.org/w/index.php?curid=579075
Gerald Holtom created the symbol for the Campaign for Nuclear Disarmament in 1958, to be used in a poster for a protest march. It is based on the flag positions in the semaphore flag alphabet for N and D.