Month: November 2015

A report on further experimentation with Julian Rohrhuber and his students at the Institute for Music and Media in Düsseldorf during our coding with weaves and knots remote seminar this week.

As we have so little idea what the Inca are telling us in their Quipu, it seems appropriate to add a cryptanalysis approach to our toolkit of inquiry. One of the first things that a cryptanalyst will do when inspecting an unknown system is to visualise it’s entropy in order to get a handle on any structures or patterns in the underlying information. This concept comes from Claude Shannon’s work on information theory in the 40’s, where he proved that information obeys fundamental laws of physics. The concept that information and “cyberspace” may not be as intangible and otherworldly as we might believe (in fact is grounded in physical reality along with everything else) is one of the recurring themes of the weavingcodes project.

Shannon’s innovation was to separate the concepts of data quantity from information value, and he claims that information is equivalent to surprise – the more surprising a piece of data is, the more information it contains. Conversely a piece of information which we expect to hear by definition doesn’t really tell us very much. The potential for some data to be surprising (or more specifically it’s potential to reduce our uncertainty) can be measured statistically, with a quantity he called entropy, as it is analogous to states in thermodynamic systems.

Shannon defined a generalised communication system, which is handy to give us a way of reasoning about our situation in relation to the Inca. Our main unknown is the source of the messages they are sending us, are they accounting information, calendars or stories? We know a bit more about the transmitters of the messages, the khipukamayuq – the knot makers and quipu keepers. At the time Shannon was working on information theory, he was part of the start of the movement away from analogue, continuous signals and towards digital signals – with advantages that they are highly resistant to noise and can be carried further and combined together to increase bandwidth. Quipu are also mainly comprised of digital information – the type of a knot, the number of turns it’s comprised of or the twist direction of a thread are all discreet (either one thing or another) and therefore highly robust to material decay or decomposition. We can still ‘read’ them confidently after 500 years or more without the digital signal they represent being degraded too badly, if only we could understand it. At the same time, none of us working on this have access to a real quipu, so our receivers are the archaeologists and historians who study them, and compile archives such as the Harvard Quipu Archive we are using.

Although entropy is a very simplistic approach mathematically, it’s main use is to give us a tool for measuring the comparative information carrying potential of data which we have no idea about. Here are all the quipu in the Harvard database in order of average entropy bits they contain (only listing every other quipu ID):

This graph is calculated by making lists of all the discreet data of the same type, e.g. knot value, type, tying direction, pendant colours and ply direction (ignoring lengths and knot positions as these are continuous) – then calculating Shannon entropy on histograms for each one and adding them together.

We can also compare different types of information against one another, for example the main data we currently understand has some specific meaning are the knot values, partly derived from the knot type (long, single or figure of eight), which represent a decimal notation. If we compare the entropy of these we can expect them to have roughly similar average amounts of information:

The meanings of colours, ply and structure are largely unknown. Here are the knot values compared with the colours:

And this is pendant ply direction compared with knot values for each quipu:

At this point the most useful aspect of this work is to give us some outliers to inspect visually and sonically – more on that soon.

I’m collaborating on a Sonic Pattern residency as part of the Inhabiting the Hack series, where four artists are invited to spend three days thinking about patterns in sound, textile, and technology. We started with a briliant half-day workshop on tablet weaving, lead by Sarah Williams. It was good to start a tech-focussed residency with some ancient tech, blowing our minds with the complexity which fell out from simple interactions between threads.

We first learned how to do the weaving, and then how to set up the warp, getting stuck in to the weaving first, and then get a feeling for how the threads themselves play their role in the cloth which emerges. Learning how to tablet weave backwards in this way worked well, and at some point Sarah noted how weavers generally seem to do things backwards. Instruction was around sitting position, tension, and how to establish a simple baseline to understanding what was going on, to avoid being scared off by the complexity. Learning Sarah’s techniques for how to warp up the tablets felt a little like taming a wild beast.

It turned out that Sarah is the Hon. Secretary of the association of Guilds of Spinners, Weavers and Dyers, which made it especially good to see how much she enjoyed the surprises which tablet weaving threw up even in our short workshop.

We’ve been working on new approaches to 3D rendering ancient weaves, using Alex’s new behavioural language (which describes a weave from the perspective of a single thread) as the description for our modelling. This new approach allows us to build a fabric out of a single geometric shape, where warp and weft are part of the same thread.

This is mix of tabby and 2:2 twill, created by this code:

warp 12 24 ++ [TurnIn] ++ threadWeftBy'' Odd (rot 3) ([Over,Under]) 12 12 ++ threadWeftBy'' Odd (rot 3) ([Over,Over,Under,Under]) 12 12

I’m still learning this language, but more on that soon. This line produces an large list of instructions the weave renderer uses to build it’s model, turning the thread and shifting it up and down as it crosses itself.

In the video in his last post Alex describes using this to mix two separate weaving techniques together, which is one of our main reasons for developing this language – existing weave simulations cannot replicate the weaving technology of the ancient Greeks who for example, combined tablet and warp weighted weaving in the same fabric.

The second problem with weave simulations is shown by the following screenshot from a popular existing system:

Fabrics modelled in this way are considered to infinitely repeating sections with chopped off threads. There is no consideration for the selvedge at the edge of the fabric – which as we’ve shown in our past research is almost like a completely separate weave system of it’s own, and rarely considered by notation systems or modelling (and often left to the weaver to ‘livecode’). Here is a different view of the same fabric:

We can also now introduce other changes to the yarn structure, for example modifying the width using a sine wave.

I still have a few glitches to fix as you can see above, but here is a video of the development process from the first script, getting the polygons lined up, fixing the turning, adding over/under, reading Alex’s code and finally lining everything up.

Last week the weavecoding group met at Foam Kernow for our Cornish research gathering. As we approach the final stages of the project our discussions turn to publications, and which ideas from the start need revisiting. While they were here, I wanted to give local artists and researchers working with code and textiles a chance to meet Ellen, Emma and Alex. As we are a non-academic research organisation I wanted to avoid the normal powerpoint talks/coffee events and try something more informal and inclusive.

One of the original ideas we had was to combine weaving and coding in a performance setting, to both provide a way to make livecoding more inclusive with weaving, and at the same time to highlight the digital thought processes involved in weaving. Amber made vegetarian sushi for our audience and we set up the Jubilee Warehouse with a collection of experiments from the project:

• The newly warped table loom with a live camera/projection from underneath the fabric as it was woven with codes for different weaves on post-it notes for people to try.
• The tablet/inkle loom to represent ancient weaving techniques.
• The pattern matrix tangible weavecoding machine and Raspberry Pi.
• A brand new experiment by Francesca with a dancemat connected to the pattern matrix software for dance code weaving!
• The slub livecoding setup.

This provided an opportunity for people to try things out and ask questions/provide discussion starting points. Our audience consisted of craft researchers, anthropological biologists, architects, game designers and technologists – so it all went on quite a lot longer than we anticipated! Alex and I provided some slub livecoded music to weave by, and my favourite part was the live weaving projection – with more projectors we could develop this combination of code and weaving performance more. Thanks to Emma for all the videos and photos!