Thousands of people have tried to solve the puzzle (riddle) from British Secret Intelligence Service, but nobody has succeeded yet.
The first phase was available online for everyone from December to February. After the first phase, a series of complex challenges followed. Once all phases were unlocked and successfully completed, players were encouraged to email the answer to their office.
In this puzzle each square is black or white. Some of the white squares are already filled. Each row or column is marked by a series of numbers. The numbers indicate the length of the subsequent black squares and are shown in a row that appears in that line. For example, 2 1 6 shows a set of two, one and six black squares, and each of them has at least one white square that separates them.
Until February, almost 600,000 people have successfully completed the first stage of the puzzle. 30,000 players have reached the final stage, but no one solved the entire puzzle.
The riddle was designed to encourage people to make donations to the National Society for the Prevention of Cruelty to Children.
All the answers can be found HERE.