Object: solve the given Code Cracker or make your own Code Cracker puzzles.

The first six variants form a collection of Code Cracker letter puzzles.
You have to associate letters with (some of) the numbers 1 to 26.
Move any letter from the letter list next to one of the numbers in the two numbers columns.
The system will exchange all related numbers on the main board to letters.
The result should be a correctly filled crossword puzzle.

You win when you got all associations right.
As a help, the solutions for two letters are given already.

There is also a 'make your own' variant where you can construct your own code cracker puzzles from any solved crossword puzzles of size 13x13.
For details read the associated game text.
The variants 1 to 6 have been designed using this Code Cracker construction tool.

Please note that there is an alternative piece set.