The puzzle above is the simplest example of what may be called a
"three-square cover-uncover sliding puzzle".
(Note that by using a link on this page outside the game board and its
buttons you will leave the puzzle and go to a different page.)
First of all, it uses the smallest board possible, with sides of only
Secondly, the covering square is subdivided into the smallest number of
The largest of these blocks is already in the proper position and the
second-largest has only to be moved one place horizontally and one
place vertically towards the corner of the board.
Try the more complicated
7-block variant before proceeding to a
The easiest method of keeping track of the moves you make to solve this
kind of puzzle is to write down the letter of the block, followed by
l(eft), u(p), r(ight) or d(own).
If you move the same block a number of places in the same direction, you
can show this by using that number followed by the code for one move in
For example, 3Bd then stands for moving block B 3 places down, and
is short for BdBdBd.
With this notation system a solution to the above puzzle may be written as:
(There are other solutions, but they do not differ from this one in
any essential or interesting way.)
Once you have cleared the central square of this puzzle in (hopefully)
14 moves, you will see a table of three rows and three columns with some
text and figures.
This same table can be found in
System, except that the two yearly inaccuracies of 0.1% are not shown
It demonstrates how much more accurate the
Metric Calendar is than the
traditionally most freakuently used religious-imperial one.
It also demonstrates that you cannot, need not and must not take anyone
seriously who employs that freak of culture to make statistical
claims about such a thing as the differences between the economic data of
two quarters or, worse, months.