a question on cryptonomicron

somewhere between 1/3 to 1/2 of the way though the book the main characters are discussing  the building that will house a computering center. anyway there is a passage i don't understand.

there's alot of stuff (too much to copy paste) but the specific point i don't understand is

Prag prepares for the staredown. You asshole, you tricked my German—for this you shall die!

how was the german tricked? i just don't get it.

if you really think you understand the book just go to
http://newark.pardey.org/book/cryptonomicon/slide46.html
for the context please.

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