What is the name of this symbol: Circle, cut into fourths, with opposite fourths shaded in.?

Question

If you dont know what I'm thinking of here are some URLs to c it: http://m235.co.uk/images/alienware/ctu/CTU_v4_1680x1050.jpg (the main shape behind the bird)

I've seen it in more places and its starting to ware on me. Can you help me?

Answer 1

To a limnologist, that would be a secchi disk. You lower it into a lake or pond to determine how clear the water is.

Answer 2

the closest that i can find:  either exclusive OR (XOR) or a tensor product

http://en.wikipedia.org/wiki/Table_of_ma...

Answer 3

I am a drafter for a civil/structural engineering company.  In the construction field that symbol is most commonly used to represent a soil boring on a set of plans.  As for using the symbol on crash test dummies, those symbols are used to help researchers during the review of slow motion video taken during a test.

Answer 4

This warns about Dangerous radiations

like X rays, radio active elements like Uranium

Plutonium

Answer 5

In the first, it's just an easily recognizable, high contrast image with a single well-defined point.  When they analyze the video from a crash, they can measure exactly how far and how fast each head moved.  A construction company (per the second) would again use an image like this for alignment.  I doubt the third is particularly significant or related.

Answer 6

I'm a civil engineer and on some engineering plans it can be used to mark where a soil boring has come from on plans. I've also see it used as a symbol for water valves on a proposed water line.