Decryption sheets similar to Zygalski sheets used to decipher Enigma
This is a color image of a display three decryption sheets laying on top of each other with square grid patterns and the horizontal rows labeled with letters of the alphabet A through Z. Most of the image is brown in color except for the white squares. This is only a partial view of the sheets as the photo only shows the upper left portions. The top most sheet is labeled "Right-hand Rotor Ring Setting" and with the letters A to W vertically. Several of the squares are white. The middle sheet is labeled "H" and has letters of the alphabet from Z to C vertically. Several of the squares are white. The bottom sheet is labeled "I" and again has letters from Z to A vertically. These sheets are similar to the early Zygalski sheets created by the Poles to decrypt Enigma.