(related to Problem: The Four Postage Stamps)
Referring to the original diagram, the four stamps may be given in the shape $1, 2, 3, 4,$ in three ways; in the shape $1, 2, 5, 6,$ in six ways; in the shape $1, 2, 3, 5,$ or $1, 2, 3, 7,$ or $1, 5, 6, 7,$ or $3, 5, 6, 7,$ in twenty-eight ways; in shape $1, 2, 3, 6,$ or $2, 5, 6, 7,$ in fourteen ways; in shape $1, 2, 6, 7,$ or $2, 3, 5, 6,$ or $1, 5, 6, 10,$ or $2, 5, 6, 9,$ in fourteen ways. Thus there are sixty-five ways in all.
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