Detailed instructions for working a group puzzle of type 'Jack'
This is a signature puzzle named 'Jack'
The 4 elements in each group of this type of puzzle are: J, A, C, and K.
Every group in the puzzle must contain exactly this set of elements.
In a Jack puzzle, each row is a group numbered as shown in the figure above.
In a Jack puzzle, each column is a group numbered as shown in the figure above.
In a Jack puzzle, each 2x2 square is a group numbered as shown in the figure above.