Seizenn offers facilities for creating patterns for stoorstalka rigid heddles.
The pattern presented here are mainly taken from the stoorstalka sets available on the site https://shop.stoorstalka.com/en/products/handicrafting-diy/yarn/weaving/
We first choose a common color palette for the Nordic patterns. In the palette creation tool
, let choose palette “30”.
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Then we will open the tool for “realistic” patterns 
In the left menu, go to the “load, Save, Export” submenu. There is a drop-down list with the different heddle models. Just choose a pattern and click on the “heddle pattern” button.
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The models available are basic, sigga and sunna. By default the models use the first colors of the palette.
Basic Pattern
Basic heddle is for simple plain weave band. 4 size are available corresponding to the total number of threads : 31, 63, 103, 131.
For “basic 31” you get this default pattern.
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You can then modify it to get, for exemple (beginner-level-1/weavekit-basic-vardag-red) ,
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Sigga Pattern
Sigga heddle are for dual color float pattern. There are three sizes , 8, 16, 24, corresponding to the number of floating threads.
The Sigga 8 default pattern looks like 
You note that there are 8 green dual color floating thread. Pattern is 35 threads wide and 8 threads have dual colors.
Using the dual color mode and the pickup mode you can get a pattern like (https://woolery.com/stoorstalka-band-weaving-kit-advanced.html)
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Sunna
Sunna heddle is for pickup pattern (baltic). 4 sizes are available, 5, 7, 9, 13 corresponding to the number of pickup dots, the width of the pattern. Sunna 5 pattern has a total of 37 threads.
The Sunna 5 default pattern in seizenn is
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You can modify it according to https://shop.stoorstalka.com/en/products/handicrafting-diy/yarn/weaving/band-weaving-kit/professional-level-3/weavekit-professional-yellow-red.html using the pickup tool.
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You could also use the grid tool to create you pattern
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Application
This is a personnal project using Sunna 13 heddle. I didn’t use all the border holes.
Starting from default Sunna 5 pattern, you can do this in Seizenn by removing threads and using arrow buttons to move threads and patterns.
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