Hard Puzzle is an iPhone app challenging you to change O's to X's... At first it seems there is no pattern to the solution, but then...

A few fun facts about Hard Puzzle;

Hard Puzzle was designed specifically with *speed* in mind; the creator of the puzzle can solve it completely in about 17 seconds. Maybe you can do it faster!

The sequence used in the solution is inspired by several ancient (and some not-so-ancient) puzzles, including;

Chinese Rings / Baguenaudier, invented in the 1600's
Tower of Hanoi, from around 1883
Spinout, patented in 1970
The Brain, ??? 1960's? (this one used to be our favorite)

The solution for Hard Puzzle is described mathematically as a "binary code" or more specifically a "Gray code." There are exactly 170 steps to a perfect solution.

While solving the puzzle, each correct move produces 1 musical note from Goldberg Variation No. 1 by Johann Sebastian Bach, published in 1741. Bach's Goldberg Variations are called "binary" compositions, because they consist of two sections called A and B.

WARNING! SPOILER ALERT! The following text contains hints about how to solve Hard Puzzle for iPhone! Stop reading if you prefer to discover the solution for yourself!

Hints;

-There are 8 buttons in Hard Puzzle that must be turned on and off in a particular order to reach a solution.

-Consider the buttons numbered thusly;

1 2

3 4

5 6

7 8

You can only activate a button if the button number immediately before it is an “X”, and the other buttons before it are “O’s.” So you cannot activate button 4, changing it from O to X (or vice versa), unless button 3 is an “X” and buttons 2 and 1 are both “O’s.” Another example; in order to activate button 8, button 7 must be an “X” and all the other buttons must be “O’s.”

-The pattern to activate all the buttons from 1 through 6 is;

1213 1214 1213 1215 1213 1214 1213 1216 1213 1214 12

Notice the pattern “121″ occurs very frequently; a fast solution to the puzzle depends highly on your ability to execute this pattern without error many times – 42 times to be exact! Of course the number that comes after this triplet changes often, as you can see above.

The above partial solution is only 1/4 of the total moves required to solve Hard Puzzle!

© 2009 Hard Puzzle | Designed by: Sam & Neil