My father received a fascinating puzzle for Christmas, in 2004. Made by b.dazzle inc, it is the North American Birds version of their "Scramble Squares" type of puzzle (note: the one shown on their website is different from the one they sell, and the one seen on their website is also unsolvable). The puzzle consists of 9 square tiles, each tile having 4 half-birds, with one half-bird on each of the 4 edges. The object is to fit the tiles together in a 3x3 arrangement so that all touching half-birds form whole birds. The puzzle is simple enough for a young child to comprehend, but completing it isn't exactly child's play. Then again perhaps it is, since after playing with it for an hour, I concluded that an oldster like me would need to keep methodical notes to keep track of which things had been ruled out. And at that point I realized it would be more fun to write a computer program to do these methodical tasks than to actually do them.
For the benefit of those who still want the fun of solving it, I am offering a gradated series of hints, and a computer program that takes all the fun out of it. But you can click on just one hint, and you will not be shown any further hints, until you want them.
For those who enjoy computer programming, writing a program that solves such puzzles is interesting in itself. A wee bit of analysis reveals that the simple-minded approach of trying every tile in every position in each orientation, will take years to run to completion (there are 9 factorial times 4 to the ninth, or many billions, of configurations to be tested), so one needs to find a somewhat "smarter" method if one wants an answer today.
Since writing this program and this webpage I've learned that others have written similar programs, and also that puzzles of the same type are sold under many names by many companies, including Crazy Games by Price Stern Sloan, Squzzle Puzzle by MindWare, 3D Squares by DaMert, Artus Puzzle, Die verrückte Hühnerparty by Heye, Magic Square, and Red Point puzzles. See my "Further Reading" list below for more details.
Here are the hints - please start with the first one, if you still want some puzzling pleasure.
Running the program:
Click to download the ICON-translator from University of Arizona.
Further reading: (updated 2008-10-12)
"Using Backtracking to Solve the Scramble Squares Puzzle" by Brandt, Burger, Downing, Kilzer of Rockhurst University
A Scramble Squares Solver by Mark Van Dine
Crazy Turtle Puzzle, a Sourceforge project -- computer-programs, database of single-solution puzzles, many links