This entertaining puzzle has become a classic.
The original versions were inspired by "The Enigma Machine" which the Germans
used to encode and decode messages in World War II.
In this simplified version, a one-stage letter substitution is used to scramble
a well-known or humorous quotation. Your task is to unravel the quotation
by swapping letter pairs until the original message is restored.
You swap letter pairs by selecting a letter and then a second
letter using the mouse or the keyboard.
New: Lock any letter you know is right by holding down the
mouse or by using the shift key. There also is a handy Undo key
The histogram shows letter frequencies. Since E and T are the most common
letters, a good way to start is to make the most frequent letters in the
histogram E and T. Then look for words like THE, AND and A and keep
swapping letter pairs until words you recognize start to emerge.
There are two new puzzles every day. If you can"t solve
one today, come back tomorrow and see the solution.
This puzzle was first programmed in Java by my daughter, Camberley, as a
freshman class programming exercise at Harvard in 1996 based some ideas
suggested by me that were in turn based on a book called "Codes and Cyphers"
that I read when I was 10 years old. It was converted to HTML5 in 2014.