Flexagons

The January 2012 issue of ‘The College Mathematics Journal’ is a Martin Gardner Special Issue. It includes three papers on flexagons which were introduced to a wide audience 50 years ago by Martin Gardner. For my paper see Gardner 13-cmj011-014-pook

Comments

I welcome comments on the content of my website and, where appropriate, try to respond to them promptly. Comments are moderated, and only accepted if they are relevant and appropriate. In particular, comments that are advertisements are not accepted.

Smith Granddaughter Clock

A Smith synchronous electric granddaughter clock, which I have previous referred to as Model GM 30, is actually a Gibraltar, date range 1935-1939. This date range matches a known date of 1935 for one particular clock. I have updated descriptions on the Smith page to include the correct model name, and apologise for publishing misleading information.

My research into synchronous electric clocks is an ongoing activity, and I always correct errors in clock descriptions as soon as I become aware of them.

Synchronous clock queries

I welcome queries on synchronous clocks. If anyone would like a private response, rather than a public reply to a query, please indicate this in the comment. I will then send a response by email and not approve the comment for publication.

Website Update

I have updated the subpages  on various makes of synchronous clocks to included photographs of most of the clocks described. As before, more information can be found by clicking on a link. i have also added descriptions of several more clocks.

Flexagon Lovers

Does anyone know what has happened to the Flexagon Lovers group hosted by Yahoo?  The site is still there, but there have been no new postings since the beginning of the year. A posting I sent in January has never appeared.

Serious Fun with Flexagons

A substantially cheaper paperback edition of ‘Serious fun with flexagons. A compendium and guide.’ is now available from Springer to people who have access, through their libraries, to Springer ebooks. The text is identical to the original hardback edition. The book can be read online. Go to www.springer.com and search for Pook.

Some Quotations

I’ve added the following quotations to the Quotations page.

If it ain’t broke, don’t fix it.
Bert Lance. Nation’s Business. May1972.

The buck stops here.
Harry S Truman. Motto.

Nemo me impune lacessit. (No one provokes me with impunity.)
Crown of Scotland and all Scottish regiments. Motto.

Only one-third of human beings are asleep at one time, and the other two-thirds are awake and up to mischief somewhere.
Dean Rusk. Attributed.

Synchronous Clocks

I’ve recently uploaded brief descriptions of several more synchronous clocks. These include a Smith Craven’A’ advertising clock at S 124 Smith A and an elegant Siemens wall clock in a porcelain case at S 121 Siemens A

Pyramid Flexagons

Traditionally, the leaves used to construct flexagons are flat convex polygons that are hinged together in a band. The leaves are often regarded as rigid, although leaf bending is sometimes allowed during flexing. However, there is no mathematical reason why leaves have to be flat. The only restriction on their shape is that adjacent leaves must nest without interference when folded together. A pyramid flexagon is a conventional flexagon with the flat leaves replaced by appropriate open based right pyramids. For descriptions of three examples click the following link, and then on the link that appears in the preview. Pyramid Flexagons 2