File for laser cutting girih tiles

The laser cutter reads vector graphics; a red line means 'cut' and a black surface means 'engrave'. I made an svg file with the girih tiles placed side by side. You can download the file, visit your local Fab Lab, and make your own girih tiles! There is some room for improvement in the file - each side is cut twice, which is a waste of time and possibly burns the acrylic more than necessary. This file works fine, but it would be even better if one would remove those double lines.


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Contents of the file:



At the sides of each piece, there is a 'teeth' pattern, which I put there to make the pieces align better. Another 'innovation' is the double black line that forms the outline of a rope tied in an infinite knot, with a crossing at the sides of each girih piece. It turned out that it is possible to design the tiles so that the rope regularly passes above, then below, then above... for any pattern that one builds with them.

More pictures of the tiles and of the laser cutting process.

Laser cutting Girih tiles

The laser cutter at Fab Lab Groningen.


The machine can both engrave and cut. It is almost magical to see one's design gradually appear as a physical object. Here the laser is cutting our girih tiles from a 3 mm acrylic sheet. The machine does the engraving first, one sees the knot pattern formed by the pieces appear. This is how girih patterns typically look when they are used for decoration, you see the knot pattern but not the borders between the pieces. Then the pieces are cut. The cut lines are quite different from the lines drawn on the tiles. Probably this is part of the reason for the complexity and beauty of girih patterns.


I find the Fab Lab concept fantastic, giving anyone the chance to use this kind of professional fabrication machines. They had 3D printers and a CNC mill as well. Not to mention the nice people at the Fab Lab, guiding me through the process of using the laser cutter!

Someone else also made a set of  laser cut girih tiles, at the Fab Lab in Lille. Some more pictures of our tiles, and the svg file for the laser cutter.

Platform game, level 4

After many months, we finally have a new version of the platform game! As always, it comes with a new level.

Download the game here: for Windows, Linux(32) and Linux(64). See these instructions for installing it on different platforms.

Acrylic Girih Tiles

We stumbled across the local Fablab on our holiday in Groningen, the Netherlands. We wanted to try their laser cutter, so I designed some girih tiles in Inkscape. These things have so many wonderful features, so more posts to are sure to follow - the laser cutting process, and the svg file for the laser cutting machine.



A nice collection of girih cut out of paper.

Adolescent Ducks

Another trip to the botanical gardens, some weeks later - the ducklings are now half-grown, and as tame as ever. They seem to spend most of their time snoozing in the sun and scratching their new feathers.

Street Things Marburg, Part Two

Street Things Marburg, Part One

Glass Beads

Got some new glass beads, in three sizes - small, tiny, and ridiculous.

The New Grey

Since I had almost no grey Lego bricks in my old collection, I ordered some new ones from Pick-A-Brick. I realized that the color was different - the new grey bricks, on the left, make the old ones on the right look even older and dirtier than they are. According to Brickipedia, this new color, bley, has some blue in it and replaced the old one in 2004. A pity, since the old grey bricks are among the most stylish objects I know.

UPDATE. Fascinated by this shape, I made a painting of it.

Glad Morsdag

From a trip to the botanical gardens yesterday.





Met a family of ducks.

Making Soap

We followed this tutorial, based on this recipe for transparent soap. We were slightly short of castor oil (since 250 ml oil does not weigh 250 g...), but we substituted olive oil for the missing part. This German soap calculator was handy to get the substitution amount right.

Some equipment and ingredients. For alcohol, we used a bottle of Stroh 80 rum. This gives our soap a hint of red-brown color and a nice rummy smell as well, at least during the soap-making. On the right, some sand cake molds, pudding cups, and a plastic heart-shaped bowl, to be used as soap molds.

We heated the oils and dissolved the lye in water. Here we pour the lye solution into the oil, then mix with a blender. This is where the chemistry happens, the lye and the fat react, producing soap and glycerine. The mixture quickly became opaque and quite thick. The thickened mixture was kept in our small oven on 80 C for one and a half hour.

After staying in the oven the soap was quite hard and dry. Here we add solvents - first alcohol and glycerine, then sugar solution. We had lots of small soap pieces floating around, but after sitting in the oven again, the solution cleared up miraculously.

Time to add pigments and fragrance oils! For color we used food colorants and some of my fluorescent pink pigment, dissolved in alcohol. For fragrance, we had rose geranium and grape fruit essential oils. The grape fruit smelled very nice, but was much weaker than the rose oil in the finished soap.

Then the soap was poured into forms, and put in the freezer to harden. Ice cube trays from IKEA  gave nice little soaps.

Some of the finished soaps! We were apparently a bit heavy-handed with the food colorants, and some of the soaps are really too dark to be transparent. The green and the fluorescent pink (see top of post) were just perfect.

Street Things Turku, Part Two

Tiny, feeble measuring points. Approximately natural size.

Striped Blue Beads

An experiment with making 'length-wise' striped beads of Fimo polymer clay. The transparent greenish stripe is 1 part transparent white, blue, and green, correspondingly.

Another set of beads - dark sparkly green-blue with some pink mixed in.

Bonus - wave patterns forming in the sink when sanding these blue beads.

Street Things Turku, Part One: Round Covers