OK. Back to basics then, anyone?
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https://web.archive.org/web/20100327210623/http://www.bitcoin.org:80/faq"... What is Gapcoins value backed by?
Gapcoin is valued for the things it can be exchanged to, just like all the traditional paper currencies are.
When the first user publicly announces that he will make a pizza for anyone who gives him enough Gapcoins, then he can use Gapcoins as payment to some extent - as much as people want pizza and trust his announcement. A pizza-eating hairdresser who trusts him as a friend might then announce that she starts accepting Gapcoins as payment for fancy haircuts, and the value of the Gapcoin would be higher - now it would be backed by pizzas "and" haircuts. When Gapcoins have become accepted widely enough, he could retire from his pizza business and still be able to use his Gapcoin-savings.
Currently, Gapcoin is in beta development stage, and some new features need to be implemented before the system is well suited for real use. The system already works on the basic level, though, and you can trade with it if you want to. ..."...
Now,
"Write the expression for the volume of a thick crust pizza with height "a" and radius "z". *
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https://www.reddit.com/r/math/comments/qwq1u/in_honor_of_pi_day_what_is_your_favorite_math_joke/c415cxa/

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SWIM added ...
Q. "What do prime numbers and stoners have in common?"
A. "The higher they are, the more spaced out they get"
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https://www.reddit.com/r/Jokes/comments/3qkaoy/what_do_prime_numbers_and_stoners_have_in_common/ 
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* Explanation:
The formula for volume is π·(radius)2·(height). In this case, pi·z·z·a.