## Version 34 Newsletter

### Kites

A kite is a four-sided polygon with edges in cyclic order AABB with the edge length A not equal to B. Hence a diamond and a square are not kites.

There are a significant number of patterns with kites but no regular polygons of star-polygons. This presents a problem, since regular polygons and star-polygons forms the basis of many searches. The solution introduced in this release is to regard a polygon or star-polygon composed of kites as that same as a polygon or star-polygon.

Also, the tree-searching logic directs one to the table of patterns with kites joined into polygons or star-polygons, see Special Collection: Lattice patterns.

### Chelates

Usually, a polygon cannot have holes. There is an exception: a polygon can have another polygon within it if the two edges share a single point. We call this a chelate. Some time ago, the software for drawing patterns was extended to allow chelates. We have now added a display of all patterns containing chelates.

In 1978, Tony Lee inspected a book at SOAS which had some interesting patterns. This book has been examined in more detail which has produced over 30 new patterns which can be found by using the search for the publication [shafai]. The book is written in Persian so we are very grateful to Antony Wynn who translated the captions to the illustrations for this web site.

This release contains more from this publication, especially ones with kites.

An interesting new pattern is actually a modern one. In Islamic style, the photo reveals that the pattern is produced using triangular tiles.

A simple pattern in Moroccan style appears in Grande Mosquee de Paris. Although this patterns dates from 1926, no earlier version has been found.

### Inkscape

This tool allows one to modify the PDF graphics available from this site. Of course, such modifications does not change the PDF on the web site. The Open Clip Art Library has an example of the tiles used in Moroccan Islamic patterns which can be used to create many different patterns. A second set has been added, see Decagonal set.

### Non-mathematical patterns

Some patterns cannot easily be represented in a mathematical form used for almost all the patterns on this web site. An example of such a pattern is Bourgoin, Plate 134. Construction of this pattern is shown using Inkscape It is not quite clear how these patterns should be handled, and suggestions would be welcome.

### Change of direction

It does appear that the sources of new authentic Islamic patterns is drying up a bit (with the exception of the Persian book noted above). Hence it is likely that changes to this web site will mainly be undertaking more analysis of the existing material, rather than many more patterns.

### Want to help?

There are always some activities which could be undertaken to improve this web site. Please email us if you are interested.