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3]CHECKERBOARD
3]By Todd M. Lewis
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     CheckerBoard is a jigsaw-type puzzle with a twist. Nearly any piece can
be placed next to any other piece. In fact, it has many completely correct
solutions. "Sounds simple," you say? It isn't.
     The puzzle design is simple enough. Take a checker board and cut it,
along the edges of the squares, into 12 irregular pieces. Scramble them and
put them back together. The program does the cutting and the scrambling. All
you have to do is the reassembly part.
     Operating the puzzle is simple, too. Select a piece by pointing the
mouse and clicking the left button. Move the piece with the mouse. Rotate
the piece as needed by clicking the right button. If you don't have a piece
selected, the right button operates the menu instead. When you have the
piece in position over an empty space, click the left button again to put
the piece down. You can only put a piece down in an empty space.
     The left side of the display shows three numbers labeled "Right",
"Wrong", and "Empty". The "Right" and "Wrong" numbers indicate how well the
colors alternate relative to one another on a particular layout. They should
always total 64, the number of squares on a checker board. A high "Right"
number doesn't necessarily mean you are close to a solution, only that the
colors of the pieces already on the board are alternating as they should.
     These numbers also give you some measure with which to compare
solutions. For example, a solution which measures 59 right, 5 wrong, and 0
empty is a pretty good partial solution. Some of the colors are wrong, but
at least you made an eight-by-eight square. One measuring 40 right, 24
wrong, and 0 empty would be a poorer partial solution, while 40, 20, 4,
which leaves four squares empty on the board and therefore is not a solution
at all, would be worse still. A completely correct solution measures 64, 0,
and 0.
     Now, on a real checker board, the lower right corner is red while the
lower left corner is black. We don't worry about such things, though, since
a 90-degree rotation can fix the problem, and because our board is red and
off-white, not red and black! The Right/Wrong/Empty measure gives you the
benefit of the doubt so the "Right" number is always the larger of "Right"
and "Wrong" regardless of which corner is red.
     It shouldn't take long. The puzzle only has 12 pieces. But don't forget
to eat and sleep every once in a while.
     NOTE: The menu includes a Print command. If you don't have a printer,
you can send the output to a file instead by using the CMD program in the
Utilities drawer of your Workbench disk. See your Amiga documentation for
details on how to use CMD.

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