“SEVEN”
is a new puzzle with which you may build many shapes, both flat and three-dimensional.
Nothing was left to chance in the initial shape. Each piece of the 14x14 square has
been logically designed :
• all the pieces are generated by a 3x3 square
• then a unit square is removed from it in every possible way
• then 2, 3, 4, 5, 6, 7 and 8 unit squares are also removed from it in every
possible way
The pieces are made one unit thick. We thus end up with 36 « reversible »
pieces, as pictured page 2 of the original problems booklet. Because of this logical
process, all the pieces but the two unit squares (pieces # 35 & 36) are different and
the family of pieces is “complete.” We can focus our attention on four
types of problems :
• “ flat” (two-dimensional) shapes
• “volumetric” (three-dimensional) shapes
Why are there two unit pieces? First, because two are required in order to fill in
pieces #4 & #9 when building the shapes. And also in order to get 196 unit cubes
overall.
Now, 196 is also the square of 14.
196 = 142 = 72 x 22 = 7 x 7 x 4 = 7 x 28
196 = (1 + 2 + 3 + 4 + 5 + 6 + 7) x 7
196 = 12 + 22 + 32 + 42 + 52 + 62
+ 72 + (8 x 7)
You will find the number 7 in many problems. The shapes you are challenged to build are
drawn on squared paper in order to show their size. Of course, these illustrations
don’t give away the actual solutions. For example, one of the possible solutions to
problem #1 is the initial shape of the puzzle. Most of the other shapes should be built
outside the wooden box using all the pieces.
