Toying with tensegrity - part 3

I guess the first time riding a bike on your own felt pretty exhilarating, but this special event just started your bike riding career. Riding in different speeds, stopping exactly where you want to, doing turns with body weight shifts, stopping without blocking wheels, stopping with deliberately blocking back wheel, riding with hands off, etc, all those skills had to be mastered later. And many accidents happened until then, but if you get on the saddle again you could experience more dimensions of bike riding.

As children we understand learning as our 'work'. Improving our skills by relentlessly exercising them provides fun and gains valuable experience. As 'grown-ups' we easily lose this experimental pleasure, in a society where money can buy anything anytime our patience grew thin. I certainly notice a lack of patience in myself, and wanted to change this a bit.

I started building tensegrity models, feel free to read about the very first steps of this exploration in part 1 and part 2. I tested my patience by ordering stretchy cord via ebay. Last friday 100m of translucent beading cord arrived, after being delivered at a wrong address first.

Finally I could go ahead and build a tensegrity tower just like I had seen it in the magazine! Or so I thought. I cut and knotted my cords tensule by tensule, tuned them so that the upper triangle seemed level in both orientations. The tensuls felt rigid, but were still tuneable. I decided to use rubber bands for the 'security triangle' first, but somehow it just collapsed the tower.

I studied the photos from the instructions, and realised how much imagination and spatial thinking I need to transform the visual 2d information into a tactile 3d idea. I managed to tune a 4 story tower to keep it stable, sat back and I wondered why it still had only little resemblance to the tower I wanted to build. I turned the tower a bit and noticed its fragile balance. Instead of a lean pointy thorn I build the leaning tower of Brunswick.

I found the model lying next to the shelf the next morning, disassembled everything and started over. I wanted to figure out how the security triangles worked with only two tensuls, hoping not to collapse and entangle four level of a tower again. The way I attached the security triangle doubled some tension cords, yet all that's needed is a simple single tension line (like the ones that connect upper and lower triangle of a single tensul).

Depending on how much you entangled the different cords, it takes only little time to disassemble a tensegrity model. I reused some longer struts for the first level (and for a different visual effect) and retuned the model with the security tension cords on each level.



Attaching the connecting security cords took me a fair bit of fiddeling. They improve the balance of the tower, although I still hardly know it all works together. I learned to appreciate having rubber bands lying around handy, although I went back in this case to the builders line.

Another project awaited me: The stellated tetrahedron. I gave up when I realised that I needed more stretch than the nylon string offered, not wanting to break the dowels. Now I know that my basic problems lay somewhere else: My misconceptions how to construct the structure.

If you cut away the corners of a (space-filling) tetrahedron, you get four triangular planes instead, the triangular sides transform into a hexagonal plane. Using a cord triangle for the corners seemed obvious, but somehow I thought the remaining connections would run triangular as well.

Finding an easy way to lay out the 6 struts to have 4 corners where 3 of them meet in a specific direction proved a decent puzzle by itself. I used a zome tool model, connected the upper three triangles with stretch cord, secured the resulting mini-tetra with gaffer tape, carefully removed the model from its 'mold', and secured the final corner.



I repeated this step quite often in the last few days, until I found out how connect the for triangles to pop up into a magic tensegrity structure. Depending on how solid the model is fixed at this stage, it still can be folded (or constructed in the folded state and twisted into three dimensions.



After playing around with different ways of connecting four more triangles to my structure I went back to study images and the java applet. The final structure represents a stellated tetrahedron, I simply had to install tensors along its edges.

With a better idea of what I was doing the assembly got easier. I just had to imagine in which direction the triangles rotate, and connected the closest point of these triangles. The model twisted quite a bit while I attached the tension cords, but this time I felt confident that the model would 'emerge'.



Indeed, after cutting away the tape from the first corner the rods twisted away from each other, and I looked forward to see the miracle unfolding. As I can see now, I still got some connections wrong, I fixed the structure with two corners secured. However, I had done it!

After I bit of tuning I could balance the structures on one of the cut-away corners. It does not balance on all the corners, I think the cord triangles vary too much in length. As I used all 'recycled' materials, some of the cords could have gotten a lot of prestretching. More tuning, and fixing the cords parts of the triangles, will be the next step.



I really like the stellated tensegrity tetrahedron, and it could be fun to connect either tensuls or other tetras to it. I want to use colour as well, and/or different strut sizes. Once a structure obtained its shape, I can still tune a lot around, the stretchy cord provides enough flexibility to experiment a bit.

Size matters, in this case. Longer struts make the construction a bit easier, there's more room to cut away the securing tape without getting close to the tension cords. I might run out of display space, it doesn't appear too crowded yet.

Freaky friday

I managed to make my peace with fridays. I accepted the temporary increase in numbers, and Matt changed his ways of running the friday group. I hesitated a moment when he asked me with whom I wanted a turn, luckily I decided to do (have done?) table work with him.

Enjoying the new freedom in my hips, and more connectedness of limbs and torso, I sat down with a tea to browse a bit through anatomy trains. When Ana came in, I commented 'breakfast time', but she didn't seem to want to talk to me. When I saw her cutting a loaf of bread, I started watching her hands, trying to compare her movements with the memory of the day when she cut her hand.

Then chaos broke loose. 'Stop watching me like this!' I looked at her in surprise, maybe said something like 'What?' 'You always watch people, trying to get eye contact, it's annoying me! And I'm not the only one annoyed...' I noticed her emotional upheaval, as well as my confusion. I mentioned that observing is part of our job as AT teacher, tried to make her aware of the use of the universal quantifier 'always' in her statements, to little effect.

Recalling the situation makes me aware of how well inhibition worked for me in that situation. Her tone, body language, the message itself, the group conformity call especially, all of those used to trigger easily my 'verbal fighting mode'. Yet I stayed relatively calm, I just laughed every now and then, which probably didn't help. However, I had no interest to take the bait to dramatize the situation, which wasn't too easy.

'You always look at people, it annoys me, I feel like invaded, and others too.' Whoa, here we go. Universal quantifier, external locus of control (i'm responsible for her being annoyed) and group conformity enforcer. I asked her whether she expected me not to look at anyone, and she finished our mini drama by promising a better solution.

Unfortunately, Sharon, who witnessed the situation, did not want to comment on it. I'm sure my frustration about her reply shone through, but I had no intent to inhibit my reaction. I found it hard to refocus on the anatomy trains afterwards, but I didn't want to cling to this incident while in school.

I probably learned more than I asked for, and some of my observations were confirmed. Another random group of people thinks talking about an individual instead of talking to them could change their perceptions and improve their interactions. Duncan's idea of using all the time in school to do the work suddenly seems very radical, pretty much unheard of.

Resilience. Mindfulness. I can't tell whether my non-doing contributed much to this complex web of misunderstandings. On the positive side, I might have a chance to inspect my self defence habits, I can imagine triggers coming up.

Old habits

I still haven't found much opportunity to work constructively on one very old habit, speaking. Today started with quite an amazing turn with Jenny. I did not notice the slow, gradual increase of freedom in my movements. Although I can hardly remember the stiffness in my movement, I got very aware of my availability during Jenny's turn.

More freedom means as well more chances to 'help', or forgetting to remember to inhibit. I hardly noticed a difference in sensation when I changed my thinking, inhibiting my desire to help with the movement Jenny suggested with her hands. However, Jenny allowed me enough time to inhibit and renew my directions when undoing my shoulders, leaving me with a smile and new experiences.

I worked on my speaking habits again during the performance session. Although we were confined in the tea room, the atmosphere seemed to me more cooperative than on my first attempt. I really appreciated Kaz's approach as teacher. His question posed enough of a challenge not to shoot out an answer immediately, although I needed two attempts to answer it.

At first I lost my directions quite typically, and went a bit on a tangent. After some feedback and Kaz's friendly reminder that I didn't really answer, I stunned the group by a concise one-liner. Kaz wanted to know what I learned so far about my speaking habits, and I realised that I usually ignore my (body) awareness while speaking.

Kaz didn't stop here, although he can take pride in guiding me to an interesting revelation about my habit, and allowing me the positive experience of achieving my end by the right means. He noticed that I miss out on the chance to renew my inhibition with every full stop. Instead of telling me what I do wrong, he suggested in a friendly way a different approach, giving me the chance to choose whether to identify with his criticism or not.

Kaz's way of giving feedback certainly fits into the concept of 'indirect procedures'. He doesn't impose the interpretation of his observations to a student, he just offers them. A good example to follow and study.