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How can I cut a 27×27 square into 8 incomparable rectangles?

A rectangle with width w and height x is incomparable with a rectangle of width y and height z iff $w<y\land x>z$ or $w>y\land x<z$. (Assume $\text{width}\le\text{height}$.)

All rectangles must have integer side lengths.

The book Fractal Music, Hypercards and more... by Martin Gardner says

but eight rectangles can tile a square of side 27

Please don't look in the book; there are no answers there.

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  • $\begingroup$ "(Assume width <= height)" Does this mean 4×7 and 8×5 rectangles are comparable? $\endgroup$ Commented Aug 15 at 1:53
  • $\begingroup$ @AxiomaticSystem Yes, they are. $\endgroup$ Commented Aug 15 at 1:54
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    $\begingroup$ The layman's definition for incomparable rectangles is just "neither will fit inside the other", which seems somewhat easier to grasp than the given notation. $\endgroup$
    – Bass
    Commented Aug 15 at 2:37
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    $\begingroup$ @Bass It might be possible to rotate one rectangle (by an angle that is not 0 or 90 degrees or something equivalent) and fit it inside the other. For example, a 1x6 can fit inside a 5x5 (with rotation). $\endgroup$ Commented Aug 15 at 2:39
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    $\begingroup$ @Bass's statement implies parallel edges, which would be explicitly stated in a proper description. $\endgroup$ Commented Aug 15 at 2:42

1 Answer 1

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The widths and heights of the rectangles are:

1:27 3:23 4:21 5:19 6:18 7:17 8:16 9:11

They tile the square:

solution image

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