added random stuff which hasn't beend added because yeah

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diff --git a/lib/mt_19937_tempering.txt b/lib/mt_19937_tempering.txt
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+Why can we reverse the tempering function?
+
+There are to kinds of operations in the tempering function of the MT:
+
+	1) Right shift
+	2) Left shift with an AND
+
+To undo the first operation, a simple shift is straight forward. Let's consider
+the following example of a 24-bit number
+
+	0010 1010 1011 1101 1111 0111					y
+	0000 0000 0000 0000 0000 1010 1010 1111 0111 1101 11		y >> 18 := N
+			      ^
+			      orginal string
+	0010 1010 1011 1101 1111 1101					y ^ (y>>18) := M
+
+
+On can see, that the first  18 bits of M are the same than y. That's clear,
+because we have shifted 18 new 0 into it. But now we also now N completly, since
+the last 6 bits are the first 6 of M (N is a shifted version of M).
+If you shift less than 24/2 = 12 bits, you have to do the above steps in a
+loop, because you cannot determin N completly one step.
+
+To understand why one can undo the second operation was a bit harder for me.
+For me it was the easiest to understand it with the feistel network.
+
+
+	y			y << 15
+	|			  |
+	|			  |
+       XOR<--------- F <-----------
+        |			  |
+	 \_______________________ /
+	 /\______________________