Date: Thu, 25 Sep 2003 20:38:37 -0700
From: "sZ" <keithsz@concentric.net>
Subject: NPPF Re: Re: lemniscate and bicycling

>>>Is it even necessary for the bicyclist to ride in a figure-8? Even while
riding straight, the rear wheel of a bicycle never follows directly in the
track set by the front wheel - it cuts a "straight" line through the
constantly wavering path of the front wheel. Wouldn't this be a repeating,
if irregular, lemniscate-like pattern? <<<

This discussion sounds more and more like Sherlock Holmes:

- --from 'The Adventure of the Priory School'

"A bicycle, certainly, but not the bicycle " said he. "I am
familiar with forty-two different impressions left by tyres. This
as you perceive, is a Dunlop, with a patch upon the outer cover.
Heidegger's tyres were Palmer's, leaving longitudinal stripes.
Aveling, the mathematical master, was sure upon the point.
Therefore, it is not Heidegger's track."
  "The boy's then?"
  "Possibly, if we could prove a bicycle to have been in his
possession. But this we have utterly failed to do. This track, as
you perceive, was made by a rider who was going from the
direction of the school."
  "Or towards it?"
  "No, no, my dear Watson. The more deeply sunk impression
is, of course, the hind wheel, upon which the weight rests. You
perceive several places where it has passed across and obliterated
the more shallow mark of the front one. It was undoubtedly
heading away from the school. It may or may not be connected
with our inquiry, but we will follow it backwards before we go
any farther."
  We did so, and at the end of a few hundred yards lost the
tracks as we emerged from the boggy portion of the moor.
Following the path backwards, we picked out another spot,
where a spring trickled across it. Here, once again, was the mark
of the bicycle, though nearly obliterated by the hoofs of cows.
After that there was no sign, but the path ran right on into
Ragged Shaw, the wood which backed on to the school. From
this wood the cycle must have emerged. Holmes sat down on a
boulder and rested his chin in his hands. I had smoked two
cigarettes before he moved.
  "Well, well," said he, at last. "It is, of course, possible that
a cunning man might change the tyres of his bicycle in order to
leave unfamiliar tracks. A criminal who was capable of such a
thought is a man whom I should be proud to do business with.
We will leave this question undecided and hark back to our
morass again, for we have left a good deal unexplored."

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