Photos from nature on iNaturalist

A few weeks ago, my stepson Paul recommended the website iNaturalist to me. While hiking, I always pick my camera and I really like to take photos of animals and plants. So he knew that this website was a perfect match for me. I immediately set up a profile and today I uploaded my hundredth observation.
It’s great fun to look for interesting animals and plants and then upload them to find out their name and family. But that’s not the only useful thing. The data collected on iNaturalist can be used for all sorts of evaluations to find out which species of animals or plants occurs in which places of the world. Sometimes, there are interesting discoveries of newly immigrated species.
You can also identify the observations of other people, if you are familiar with certain species of animals or plants.
For nature lovers, biologists and photo-hobbyists iNaturalist is a must-visit website!

My observations can be found here via this link.

Cosmetics for babies and children

Finally! The book “Baby- und Kinderpflege – natürlich selbstgemacht” (Baby and Child Care – natural homemade), written by my wife, was published by Freya. The book includes many basics, numerous recipes, all vegetarian, many of them even vegan, for self-stirring. In composing your own cosmetics, they are without artificial sweeteners, preservatives and allergenic perfume oils. The basic ingredients are vegetable oils and floral waters.

After we had published two ring binder books called “Naturseifen einfach selbstgemacht” (Soaps easily homemade) Baby- und Kinderpflegeand “Hausgemachte Naturkosmetik” (Homemade natural cosmetics) in our own publishing house (Waldfaun), but sell it only on the website, we are now proud that the new book is also sold in bookstores.

My wife teaches adults how to make soap and how to mix cosmetics in adult education courses. Parallel to these courses she wrote the former mentioned two recipe collections. Last year, Inés deepened into mixing of cosmetics especially for children and babies, as she had numerous requests how to do that. Children have more sensitive skin than adults.

Together we draped the mixed ointments, creams and lotions, as well as the ingredients, thus many of the photos in the book were contributed by us.

The book is also available on Amazon:

Enjoy reading and mixing, all you mothers and fathers, and also all you grandparents, aunts and uncles.


While hiking in the “Kemptener Wald” (Cambodunum Forest) in May 2015, we came upon a strange riddle. There was a tombstone with engravings on all four sides, written in gothic letters. There was a word looking like “Dekonomensgattin” and another one that seemed to say “Dekonomsgattin”. As you later see, this can’t be translated, but I’ll try it nevertheless: “wife of deconomist”. Strange word, we thought. Neither my wife nor I had heard of this word, so at home we started searching for it in the world wide web. We had some hits on the search machines. All of them led us to old books and to chronicles of died persons. But we did not find, what the heck this meant. Finally the enlightenment came over us: While we examined the fotos and some of the links more closely, we identified the upper case D to be an upper case O instead. The strongly decorated upper case letters of the gothic font had deluded us. They even had deluded the OCR (optical character recognition) software of the search engines.

oekonom-nicht-dekonomNow look at your own: Would you have identified this without any references? In one of the scanned books we found with the search engine, we had managed to find words with upper case Ds and Os, so we were able to compare and differentiate them.


So, finally our word “Dekonom” became the word “Oekonom” (economist) – and that’s a word we all know…

Lessons learnt? Only because you get some hits when searching the web for something doesn’t mean the information is not faulty.

More lessons learnt? Typography can be difficult. As a designer you should always be aware that using wrong typefaces or fonts can result in generating text that can hardly be read – not only for human beings.

XML Tools Plugin for Notepad++

For a class lecture on XML I searched for a free text editing tool supporting syntax highlighting for XML, check if XML is well-formed an perform validation (e.g. with DTD). After some research I found out that a plugin for Notepad++ called XMLTools. I was very lucky because I already use Notepad++ for years. The installation of the plugin was no problem and had all the functions I needed for the class. In the first lecture everything worked fine. We checked for well-formed XML, developed some CSS for viewing in the browser and finally started writing a first DTD for a XML file.
Suddenly the students had files which couldn’t be found by the plugin, when they tried to validate their XML. A popup appeared telling us that it was “Unable to load the DTD xyz.dtd”. I examined the files but couln’t find any errors. I searched the net, but although I found some (elder) questions on that error, I didn’t find an answer.
So I took the files home and did some further research (trial and error). First thought was that the coding of the files was wrong, but that didn’t make any change – same error message.
Finally, it was more than one source of error. This told me once again, that error messages often don’t describe what really was the error (and that there should be different error messages for different errors!).

  1. Every syntax error in the DTD causes the “Unable to load” error. This means, if only one bracket is missing, a wrong character or similar small errors is contained in the DTD, the popup is displayed and no validation is possible.
  2. The second source of error actually was the coding: UTF-8 coded DTD-files can’t be loaded by the plugin. We were only able to validate XML files with ANSI coded DTDs (without error!)

Pilgrim’s Hat (Way of St. James)

Some years ago we and some of our friends decided to hike along the Way of St. James in stages. It was not our goal to go on a pilgrimage to Santiago de Compostela, we simply like hiking. Now, such a thing as “the” Way of St. James doesn’t actually exist. If someone wanted to see the grave of St. James in the Middle Ages, he began his journey at the door of his home and ended near Santiago de Compostela. Today, a european nomenclature denotes only the last section (Puente la Reina to Santiago) in the north of Spain as Way of St. James, all others are now called “Ways of the pilgrims of St. James”. That said we took one “way of the pingrims of St. James” – even only a short part of it, between Christgarten and Neresheim. A really lovely church (St. Sola Church) can be found in Kösingen. The priest even showed us the rooms behind the altar, the sacristy, which at that time was not accessible for the public. On 08/21/2013 they had an article in the local press called SchwäPo. Unfortunately the article is only available for subscribers.

ScallopWhen hiking in europe, you can often find a stylized scallop by the side of the road. The icon (often in conjunction with a yellow arrow showing the direction) blazes the right trail. But why the scallop? Each pilgrim finishing his pilgrimage, was handed out such a sea shell. He pinned it onto his pilgrim’s hat, his pilgrim’s bag or his pilgrim’s pole. It acted as identification tag, so pilgrims and non-pilgrims knew, who took the cumbersome way to the grave of St. James.
Numerous statues and paintings of the Middle Ages [1] [2] [3] [4] [5] [6] [7] show St. James and pilgrims with wide-brimmed hats with these shells pinned onto. These hats were typically felted like nearly every medieval hat. The material (water, stale urine and sheeps’ wool) was cheap, there were no other resources needed for the production (contrary to other handcrafts) and even better the result was water proof and nearly fire proof.

In 2005, when my wife discovered felting, the most interesting felting objects were hats of the Middle Ages. It wasn’t a long time coming until she felted her first pilgrim’s hat. In the meantime she has created several handfelted pilgrim’s hats. I am really looking forward to see the film “Die Pilgerin” (The Female Pilgrim), where some of her hats will be seen. The film is currently in production. Here are some selected photos of her hats. Anyone who wants to go on a pilgrimage himself/herself and needs a pilgrim’s equipment, may find a handfelted hat to buy on her felting homepage Zauberreigen (magic round dance).

First lace with raw silk

After my wife started felting felt hats, we determined that tablet weaved laces are quite expensive to buy. As there are many tutorials on the net, and you do not need too much material, I decided to try this on my own. My first lace isn’t perfect, not only because I had no practice yet. The Material, self-dyed raw silk is quite difficult to weave, as I read afterwards…

Nevertheless, I am happy with it. I especially like the colors of the self-dyed raw silk (red from madder and blue from elder). This will surely not be the last lace I made.

Here you can see my first lace:

Doctoral thesis published

Finally it is done – my doctoral thesis has been published:

The dissertation called “Der Interaktionsprozess bei Tangible Interaction – Entwicklung und Analyse eines Interaktionsmodells – Richtlinien zur Verwendung beim Design” is avaliable in Verlag Dr. Hut, ISBN 978-3-8439-0836-8. It is only available in german by now.

Being a subarea of Human Computer Interaction, Tangible Interaction is a multidisciplinary area. Since the first prototypes of systems with interfaces that physically represent digital information in reality and therefor provide an easier way for manipulation, this field of application grew explosively.
New technologies allow sensors to become smaller and cheaper and monitors to become bigger. This means new possibilities for interaction between human and computer arise.
This work addresses the design of a generic model for the interaction process of Tangible Interaction.
By means of this model the process can be examined with respect to critical issues. These findings on the other hand give an approach to optimize the design of Tangible Interaction systems in providing especially focused design guidelines.

Hick’s Law

In the 50s William Hick (a British psychologist) examined the speed of perception and information processing. In his experiments he created tasks where the subjects had to select a specific information from a list of information. He measured the change of the time needed for a selection, when the list of information was reduced in size. [1]. The evaluations of the experiments resulted in a logarithmic curve. He approximated the curve with the following formula for the rate of gain of information:

Formula in MathML format (not all browsers support this by now):


Formula in PNG image format:

The entrophy H is derived from the sum of the probabilities (pi) of possible selections multiplied by a logarithmic value (where n is the number of choices). The logarithm of this suggests that human beings do not perform a linear search in lists.  We rather try to divide them into categories. This allows us to exclude half the possibilities at each step.

In HCI Hick’s law is used to compare different menu layouts in graphical user interfaces in order to determine which one is most effective.

[1]: William Edmund Hick. On the rate of gain of information. Quarterly Journal of Experimental Psychology, 4(1):1126, 1952.

Old Artist-Homepage

After several years I updated my homepage and decided to remove the design of my old artist homepage. As I liked the design, I loaded up an image where you can see how it looked like. Well, it looked nice but was not very easy to maintain if I wanted to add new images…
Here’s the old layout:

The old version of the page remains online until I decide to remove it… it is located here: Old artist pages


A djembe is a west-african drum made of hardwood and covered with goatskin. The instrument nowadays is very popular even in germany, as it has a wide variety of sound repertoir. The djembe got my attention from my wife’s bellydance music, from my hobby in the medievals and from my participation at the Musisches Zentrum at Ulm University. The band Angaheym, good friends of us, used the instrument for their bagpipe music, as it is loud enough to stand the volume of the bagpipes.

djembeSoon I wanted to have my own djembe. I asked my friends who already had djembes which qualities I had to pay attention to. In Ulm I got my “personal” djembe which now serves me well for over ten years. Even a performance with children during my alternative civilian service in an integrated kindergarten was no problem for the instrument.

Those who like african or oriental rhythms will be very happy with a djembe. Originally the drums were used as solo instruments or in an ensemble with other djembes. Nowadays, they are often used as accompaniment. Especially those pseudo-medieval music groups use the djembe in their percussion.