say your prayers

Fallout shelter sign on the side of a church (not that either would probably help much in a nuclear event).  I got to wondering about these signs and found a few interesting sites.  Turns out, this sign is out of code!  "In awarding the contract for design of the sign ... the services of a psychologist be obtained to recommend a visual symbol that could be easily identified and remembered. The sign had to meet the psychological requirements of simplicity, easy identification, retention and arresting color combination .... The color combination, yellow and black, is considered as the most easily identified attention getter by psychologists in the graphic arts industry."