January 19, 2011

What exactly IS the CTCMA’s desk calendar?

Life Overtaking Law

Although the law strives to be clear and unequivocal, there will always be hard cases in which the decision will turn on the interpretation of a disputed term. It is therefore important to be able to phrase one’s arguments and descriptions as accurately as possible. As an exercise in skill-building, I was recently asked to give a specific description of this object:

Answers relating to its purpose (a desk calendar), composition (cardboard), and origin (a gift from our friends at the College of Traditional Chinese Medicine Practitioners and Acupuncturists) were deemed to be accurate, but insufficiently precise. A fully exhaustive account would have to include the shape of the object. A good working description of the figure would be to say that it is in the shape of two hexagonal pyramids stuck together and with the ends cuts off, but this sort of language is not the sort that one uses in official documents if one can possibly avoid it. This task would require a bit of research.

At first glance, the object might be mistaken for a dodecahedron, more commonly known as the shape of the 12-sided die and possible candidate for the shape of the known universe. However, on closer inspection, this object has 14 sides, which places it in the tetradecahedron family. As this specific tetradecahedron does not appear on the list, however, the search must continue.

Two pyramids joined together at the base are known as a dipyramid (or bipyramid), and the technical mathematical term for “with the end chopped off” is truncated; therefore, a good first candidate for out shape name would be a truncated hexagonal dipyramid. However, a quick Google search reveals that this name is already being used to refer to a hexagonal dipyramid with only one end chopped off, resulting in a shape resembling a cartoon diamond that is apparently the basis for a Rubik’s-Cube-like puzzle. A more accurate name would therefore be to call it a dual truncated hexagonal pyramid. However, further searching reveals that a truncated pyramid is even more pithily known as a frustum, and a hexagonal bifrustum is in fact the exact shape we are looking for. The fact that Wikipedia has a picture to confirm this fact is helpful (although for more official purposes, it is better to cite to a more reputable source, such as Eric Wolfram’s Mathworld).

Next week: General Relativity and the Law (no, not really).