# Captain Walter Fried's Fish Notes March 1944 to January 1945

### Page 2

Tony Sale's
Codes and Ciphers

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2

Report #F 5 (continued)
Then, when the motor pattern is written above the
Delta pattern each motor element represents motor action (or inaction)
between the two elements represented by the Delta symbol immediately
below it.
These conventions make it unnecessary to do any staggering at the
begining of the message or to adopt artificial notions to the effect
that the motor cornea into play only after the first few letters. All
patterns start in a single vertical line. With these conventions the
X2 limitation acts on the motor impulse one ahead and the P5 limitation
acts two ahead. These limitations are represented by X2 bar and P5 bar but
the former is more accurately written not X2 bar. This simply means that the
pattern rnust be inversed before determining its effect on M3.
For example:
X2 .xx..x.xx..x.
X2 ..xx..x.xx..x
X2 .x..xx.x..xx. Blanks at beginning
P5 ..x.x..x.xx.x. in x2 and P5 are
P5 ....x.x..x.xx. filled in with dots.
MB .x.x.x.x..xxx.
MT .xxxxx.xxxxxx.

Symbolically: - MT - MB (not X2 one back + P5 two back)

The symbol ?U? designates Boolean addition, the relations of which are as
folIows:-

. + . = .
. + x = x
x + . = x
x + x = x

All of this is, of course, only a formalized way of saying that a motor cross is
compelled if X2 one back combines with P5 two back to produce a dot.

4. Sgt. Vergine was required first to do some enciphering and
deciphering to farniliarize himseif with the operations and conventions.
He was then given two problems - (1) to recover MT and all X and Psi
patterns arid their settings being known and (2) to recover X3 and Psi3
knowing MT and the patterns and settings or the remaining X and ?Psi?
wheels.

5. Additional Synbols and Elementary Formulas

MOST SECRET

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