Big Bang Theory - Knock Formula T-Shirt Color:Green Show your love for the

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Big Bang Theory - Knock Formula T-Shirt Color:Green Show your love for theSheldon poses against the Fibonacci spiral in a Lantern inspired graphic on the front of this green, 100% cotton t shirt from the Big Bang Theory, with his tradmark door knock mathematicized on top. You may not know the math, but you'll know the knock for sure.