XYZZY: a mathematics 'in-joke?'
Ron Hunsinger believes there is a more meaningful origin to the 'XYZZY' word:
"[XYZZY is] taught by math teachers the world around as a mnemonic device to remember how to do cross products.
| "When I first played Adventure, finding 'xyzzy' in it was like finding an old friend in an unlikely place. Or an inside joke." -- Ron Hunsinger |
"'Cross products?' you ask.
"Indeed. The cross product of two three-dimensional vectors is the vector whose length is the area of the parallelogram with the two given vectors as adjacent sides, and direction perpendicular to the plane of that parallelogram.
"There is a 'simple' formula for the cross product. If A = B x C, where A, B, and C are the vectors (Ax, Ay, Az), (Bx, By, Bz), and (Cx, Cy, Cz), then:
Ax = By Cz - Bz Cy"Notice that the second and third equations can be obtained from the first by simply rotating the subscripts, x -> y -> z -> x. The problem, of course, is how to remember the first equation.
Ay = Bz Cx - Bx Cz
Az = Bx Cy - By Cx
"You do that by remembering the 'magic word,' consisting of the subscripts, taken in order: xyzzy.
"And that, friends, is the origin of the magic word xyzzy. This use of the word was around long before Adventure (or Colossal Caves or whatever name you knew it by) was ever written.
"When I first played Adventure, finding 'xyzzy' in it was like finding an old friend in an unlikely place. Or an inside joke."
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