Make the first cut with a width of 1/5, the second cut perpendicularly with a width of 1/4. Repeat the process with ever wider widths (4/15 and 3/8) to keep the same area until the last cut halves the remaining piece. This gives a total perimeter of 10 1/6 or about 10.17.
The best design for five pieces using cuts that are parallel to the edges of the original square is shown in this figure:
This gives a total perimeter of 4(2 + 1/sqrt(5)), which is about 9.8.
- For nine pieces without the child-cut rule, we get this beautiful design:
It gives a perimeter of about 15.3.
- The best design for five pieces without the child-cut rule that permits cuts at an angle to the original edges is shown here
The slant is about 19 degrees from the horizontal. This gives a total perimeter of under 9.4.
T.J. Takei provided these solutions. For the tilting calculation, he used the free software Gnu Octave.
- The best design for five pieces using cuts that are parallel to the edges of the original square is shown in this figure:
This gives a total perimeter of 4(2 + 1/sqrt(5)), which is about 9.8.
