Big Bertha Thing spider
Cosmic Ray Series
Possible Real World System Constructs
http://web.onetel.com/~tonylance/spider.html
Access page JPG 11K Image
Astrophysics net ring Access site
Newsgroup Reviews including uk.rec.cycling

Drawing of a clockwork spider wheel and hairpin.

Extract from Introductory Chapter;-
The "Spider tops," which are frequently sold in the streets of London,
consist of a heavy little disc mounted on a spindle (Fig. XIV.).
When the disc has been set spinning a small curved piece of
metal is placed to touch the toe, and at once begins to slide round it,
first the side (a) in the figure, and then the side (b),
the motion continuing backwards and forwards till the top comes to rest.
The fact is that the toe is magnetic, and this being the case it is easy
to see that the rolling of the toe on the side of the metal produces
the motion.