Five-sided Christmas Star Pastries

This is my version of a julstjärna, a traditional scandinavian Christmas pastry, which always has four arms. I wanted to expand the concept a bit.



Here is how to make it! The traditional four-sided julstjärna is made from a square piece of dough, so our five-sided ones are made from pentagons. A pentagon is of course a much less optimal shape for cutting up the dough sheet, but this is compensated for by the sublime beauty of the finished product!

Cut from each corner towards the middle, add a blob of plum jam. Fold one corner from each flap over the middle of the pastry. Adding some water to the surface as glue, squeeze until the folded corners stick together.

Color mixes for pastel beads

I wanted to make colored translucent beads from Fimo polymer clay. I think the ready-made colored 'translucent' Fimo is too strongly pigmented, and not so translucent. The idea here is to reduce the amount of pigment, by mixing in unpigmented (i. e. 'white') translucent polymer clay.

Unpigmented clay is very soft, almost too soft to form into beads with any precision. The unpigmented clay in the reddish-violet beads above on the left was a bit dry, which made it much easier to control. But when baking, the dry clay produced a lot more of whitish flakes or stripes you can see in the picture above. I don't mind so much though, it looks a bit like some kind of stone.

I played around a bit with mixing different colors with varying intensity and lightness, to get the shades I wanted. The glass beads in the picture below served as inspiration and goal, to keep the colors subtle and counteract the temptation to create super-bright shades.



It's impossible to get an accurate idea of the color of these low-pigmented mixes while actually mixing them. Unbaked (in the upper half of picture above) they look almost completely white, since they get translucent only during baking. That's why a color chart comes in handy!



To read the chart: '1 blue + 1 violet + 32 white' means that I mixed 1 part translucent blue, 1 part translucent violet, and 32 parts 'translucent white' (i.e. unpigmented) Fimo polymer clay. In practice, I used one stripe (one eight of a packet) of unpigmented clay, and one 32th of a stripe each of the blue and violet clays. So one part is here just a tiny amount - unless you want to end up with piles of pastel clay.

The conical turquoise beads are made with a bead roller, the other ones I formed by hand. They were all sanded and polished after baking.

For the brownish ones, I mixed in a bit of green, as you can see, to get the saturation down. The result it a bit too reddish for my taste. My favorites are the darker turquoise and the bluish violet. Most of these semitransparent pastel colors would probably look nice layered with opaque white!

Iridescent frying pan

Our stainless steel frying pan with colorful patterns. Frying stuff in this pan is not particularly nice, since everything, including bacon, seems to stick unless I add lots of fat. The colors offer some consolation, though. I suspect these colors appear due to light interference in a thin film of oxide on the pan's surface.


This picture of a Bismuth crystal from Wikipedia shows the same effect. The crystal is covered with a thin oxide layer. When light reflected from the top and bottom of the oxide layer interfere, the colors appear. I like the G-shaped growth patterns in this picture even more than the rainbow coloration.

Favorite Games: Nethack

Nethack A classic. You are an @-shaped hero, and your goal is to explore a dungeon filled with monsters (mostly letters) and treasures (gold $ and gems *) and other objects. I haven't played this one seriously for a while - it is much nicer to play on a full keyboard with a number pad, and I seem to usually sit at a laptop. This is a very addictive game, once you get past the initial steep learning curve. For this post we wanted a couple of screenshots, and once we started playing we got hooked again. We even learned to play without the number pad.

While exploring the dungeon one finds weapons (, armor [, and spell books +, and gets tougher by gaining experience and by learning new skills. Nethack is fun because it is so unpredictable. The ascii graphics is very simple, but the world of Nethack is complex. Monsters can interact with each other and with the world around them. You never know what will happen next, and the text description of the events in the dungeon forms an unpredictable story - sometimes a completely absurd fairy tale.

I grew up playing Nethack on DOS, and liked the way the map is drawn there with full lines for the walls. It is tricky to get this graphic mode to work in a unix terminal, for some reasons connected with different character sets. Anyway, there are several solutions. I installed the program konwert, and ran Nethack in this way on one of the text mode consoles (control+alt+f1):

nethack | konwert cp437-utf8

Then simply enabling IBMgraphics in the in-game options make the graphics look as it was meant to.



Taking screen shots of a text mode terminal is something I have never needed to do before, but it is possible with the snapscreenshot program. I ran it in this way, in a text-mode console, with Nethack running in console 1:

sudo snapscreenshot -f8 -c1 -x1 > screenshot1.tga

In an X-term window snapscreenshot does not work.

The Favorite Game series

• OpenTTD a.k.a. the Train Game
• Nethack
• Widelands

Dancer - a Processing test

A post on bitCraft inspired us to try the Processing language, a simple programming language for drawing interactive graphics and creating generative art. People have made some really fun and amazing stuff. Your program, called a sketch, can then be exported to all kinds of media platforms.

My program is a tweaked version of the program's own Brownian motion example. I added some cursor interaction and some forces, played around with the colors.

Moreover, I learned how to display the resulting processing sketch in blogger from here. Basically, I had to host the web page somewhere else, and then include it with an iframe.

Girih Flower

The fivefold rotational symmetry of Girih tiles is just the thing for creating nice flowery shapes. Happy birthday Fredrik!

Boxing the 'Berry

The raspberry router of an earlier post turned out to work well, but it definitely needs an enclosure. The fast & easy solution - put everything inside a plastic Smart Store box! (The same kind of box we modified for storing Legos.) The box contains a USB hard drive, as well as the Pi and GSM modem, so we can use the Pi as a file server.

The Pi, the network switch, the USB hub and the hard drive each has its own power supply, so we included a power strip in the box. The many power sources take up a lot of space in our current system. If all the devices could share one, the system would shrink considerably.

Each machine has its own LED, and at night, the whole thing looks like a box of holiday decorations.

The box is kept slightly ajar for the cables going into the box, which seems to provide enough ventilation as well. Measuring the raspberry's CPU temperature with

cat /sys/class/thermal/thermal_zone0/temp

consistently reports around 46 C.

This setup turned into a surprisingly nice media player as well, once I connected our old TV set to it. We have no keyboard connected to the Pi, so we just ssh to it and run the omxplayer. I plan to give XBMC a try later, but getting it set up on a standard raspbian systems seems rather involved.

The current setup is somewhat temporary - in the future, I hope to put everything inside the case of a desktop PC, to function as a power conserving and silent always-on server, independent of the main PC.

Let's celebrate!

...with a gif!

Happy Father's day!

We have no cute ducks to post today in celebration, so we post a picture of bread instead.



This is what happens when one forgets to add yeast when operating the bread machine: a very flat bread. We are happy to report that it tasted good nevertheless, the structure was just a bit more compact than usual.

Favorite Games: OpenTTD

This is the first post in a small series about computer games I like. I plan to focus on open source and independently made, or just plain home made, games. Suggestions or tips are naturally welcome in the comments!



The first game is OpenTTD. This is a great game for us who did not get a model railroad when we were kids. OpenTTD is an open source variant of Transport Tycoon Deluxe from the 1990:s.

The aim is to move cargo, mail, and people between cities and factories, and of course to generate profits for your transport company. There are many vehicles to choose from, but trains are by far the best. Building an efficient railroad network with good-looking and optimal intersections is a real challenge. When a city receives good transport service it grows, and getting the cities to grow as large as possible, extending your customer base, is one of the main goals. The game can be a bit stressful when there are hoards of people in each city waiting for your trains (if you're the type to care).

I have played OpenTTD at LAN parties, which is great fun. I prefer cooperative multi player games, in which one can build huge railroad networks together with friends. The MIDI music in the game is great, both the original tunes and the free ones composed for the open version. An active community has grown around the game, with a forum and a wiki. Railway signals, for example, is a complex topic, luckily there is good help in the wiki gameplay manual.

As a bonus, one learns geography when playing scenarios set on real-world maps, such as the town of Urk in the Netherlands on the screen shot above.

The Favorite Game series

• OpenTTD a.k.a. the Train Game
• Nethack
• Widelands

Circle Stickers - Lots of Dots

One great thing about Germany is the abundance of small, inexpensive round paper stickers - supposed to be used for archiving, I guess, but in my experience, they're also great for super-fast artwork creation, and for arranging nicely on a table.





On a side note, this company has a very impressive sticker repertoire. I haven't yet seen a shop that would sell all of these, not even in Germany.

Raspberry Router

I wanted to set up my Raspberry Pi as a 3G router for my small home network,  and as a file server too. It worked out nicely, so here are some notes and links that helped me.  My internet connection is provided by a USB GSM modem (Huawei E173), so the first task is to get this device running on the Pi. This was surprisingly easy, thanks to the sakis3g script.

I learned that once you start messing with the network, downloading new stuff gets tricky - so it's best to get everything at once.
sudo apt-get install ppp isc-dhcp-server usb-modeswitch 
and download sakis3g
wget "http://www.sakis3g.org/versions/latest/armv4t/sakis3g.gz"

EDIT: The Sakis3G web page is down at the moment, but a local copy of the script is here: sakis3g.gz (version 0.2.0.e).

The Pi can probably not supply enough current for the 3G modem through the USB ports (thanks for the tip), so I connected the modem through a powered hub. Without the hub, the modem did not work.



The sakis script was easy to use, it asked me to select my modem and then the network name (APN). When the connection works, one can write the selections in a configuration file to avoid having to enter them again. In sakis: "More options..." -> "Generate success report" shows a lot of info. Last in the list, there are the options needed to connect. Copy these (except  --console and --interactive) to the file /etc/sakis3g.conf with one option per line. Sakis does not like any extra whitespace on these lines. Now it should be possible to connect with  a simple sudo sakis3g connect.

I found a nice guide to setting up the pi as a router. This worked well for me, I just had to change which network interface is connected to the local network (eth0 for me) and which is connected to the outside (ppp0).






A small complication has turned up with the GSM modem. The modem is a multimode USB device, and must be switched into the correct mode before actually working as a modem. Sakis handles this automatically (using the usbmodeswitch program I installed above). The trouble is, that when the modem is switched, it changes its USB device ID. So the device option to pass to sakis is different the first time and any later time sakis is run without unplugging or powering down the modem in between.
The broadband company seems to drop the connection after 24 h. I think I will put a cron script for reconnecting at 5 in the morning or so. I came up with the following command for finding the current USB ID of  the modem and passing it to sakis.
sudo sakis3g connect USBMODEM=\
`lsusb | grep Huawei | sed 's/.*ID \([a-f0-9:]*\) Huawei.*/\1/'`
sed is a strange creature! grep finds the relevant line, and the sed command extracts the ID number between 'ID ' and ' Huawei'. This is of course assuming that exactly one huawei device is present.

I post some of the configuration files here. In this later post, I added a WLAN stick and got the Pi set up as a WLAN access point, these files are for a WLAN device as well. If you don't have one, just ignore those sections.
my /etc/networks/interfaces:

auto lo
iface lo inet loopback

auto eth0 #static address on eth0
iface eth0 inet static
address 192.168.50.1
netmask 255.255.255.0
network 192.168.50.0
broadcast 192.168.50.255
gateway 192.168.50.1

auto wlan0 #static address on wlan0
iface wlan0 inet static
address 10.10.0.1
netmask 255.255.255.0

And then /etc/dhcp/dhcpd.conf

ddns-update-style none;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;

#for the eth0 subnet
subnet 192.168.50.0 netmask 255.255.255.0 {
range 192.168.50.10 192.168.50.250;
option broadcast-address 192.168.50.255;
option routers 192.168.50.1;
default-lease-time 600;
max-lease-time 7200;
option domain-name "local";
option domain-name-servers 8.8.8.8, 8.8.4.4; #Google DNS
interface eth0;
}

#for the wireless network on wlan0
subnet 10.10.0.0 netmask 255.255.255.0 {
        range 10.10.0.25 10.10.0.50;
        option domain-name-servers 8.8.8.8, 8.8.4.4;
        option routers 10.10.0.1;
        interface wlan0;
}

Not a sixty degrees angle

The previous kind of salmiak wasn't, and this one isn't - maybe it just shouldn't be, a sixty degrees angle on the salmiak rhombus. Too bad! But at least it leaves a nice star-shaped space where the corners don't fill up in the above pattern.

Mixed Beads

Experimenting with colors while using up some old leftover Fimo polymer clay. I formed three piles of finely chopped clay, then mixed some of each color into the others. With some of the purple and blue, I re-chopped and mixed the finished chunks.

The pink turned a bit dull in the oven (thats a risk with leftovers) but the others turned out fine. The purple-blue re-chppped ones are probably the best of them.