16:45 25-05-2012
Shelley: it is. Haven't I received your message before? I remember replying that I would be interested if these watercolours concern the rhinogradentia themselves.

We can continue the conversation using (please replace AT with the @ symbol).    
20:52 24-05-2012
Shelley Reed
Is this Sigmund Nastrazzurro's site?  If so, I just stumbled across your Rhinogradentia II post from 10 July, 2008 about Dr. Gerolf Steiner.  I have several original watercolors of his that my father bought from him in Germany in 1946.  I'm trying to find out what their value might be. Might you be able to help? Many thanks, Shelley
22:47 15-05-2012
@Gabriel - Wow! That looks great! =) More complicated than I thought though... =D
21:48 15-05-2012
A better design posted instead (Original deleted)
The segmented ring looks more efficient because segments can achieve the desired angle at each step in the cycle.
16:15 13-05-2012
I managed to draw a Google-Sketchup illustration. If you access the 3D warehouse, it is named "ring-shaped object moving in water" and has a narrative as well.
Sketchup is not exactly suited to handle realistic behavior of bending objects, so I had to manually tackle some of the broken lines created. You will notice the surface is too bumpy and bends are slightly asymmetric, but to view it, keep the camera located in the same position I saved file with. The flat ring on the left is the position at rest, the sequence is from left to right, then the flat ring on the right is the final position at rest, after one cycle.
14:36 13-05-2012
Pete: sorry for having made you wait. I do not know whether or not the Festo/Thomastapir structure is one of many similar structures. The video you supplied shows that more than one is possible, but whether it can be generalised I do not know.  

Gabriel: your first solution is one I also envisaged. I think I understand what the Möbius one would look like, but a drawing would definitely help explain how it works...
00:49 13-05-2012
Thank you Gabriel!
Oh, I'm sad to hear about Nereus... =(

00:01 13-05-2012
Yes, the Nereus site is gone through no fault of Evan/Empyrion, but reliable sources (those would be Evan) inform me that he is thinking about a solution...

I'll get back to the subject of revolving rings later...
22:01 11-05-2012
Good news and Bad news:
21:32 11-05-2012
Nereus is gone?  (i clicked the link, and was told the website no longer exists)
21:18 11-05-2012
I think there are two possible ways to create propulsion with a ring-shaped creature that turns inside-out. One way, is to have fins all-around. preferably along the inner and outer rims of the "doughnut" structure. The fins may be connected with a skin-membrane, like the webbed feet of a duck. As the long flesh rolls inside-out, the fins are extended when they are pushed backwards in water, creating propulsion. When they pass through the inside and move forward, they are folded and offer little resistance to water. This asymmetry between the front-moving fins and the back-moving ones is what creates the net propulsion.

The second way uses the body without the fins. However, the doughnut does not have a round cross-section, but the cross-cut is rather flattened. It would be rather complicated to create a "net" propulsion, i.e. the difference between the forward-propelling rim and the backward-propelling rim would be small, and that means wasted energy.

I thought of one way to solve this problem, if you think of a Möbius strip. However, the strip I think about has two opposite quadrants facing the water at 90 degrees, like a knife laid on its side on the table (therefore "paddling", and the two remaining quadrants are at a zero angle with the water, like a knife in position to cut through butter. (Therefore "cutting" forward through the water)
The idea is that the ring bends in a way that the two paddling quadrants push the two cutting quadrants forward. At the end of each stroke, the paddling and the cutting sides switch roles and then start a new cycle.
It is still a problem, because the tissue connecting the paddling and the cutting quadrants are neither at zero nor at 90 degrees angle. This creates side-forces which tend to stretch the structure and a strong muscular system needs to hold it especially if moving fast. The use of fins seems more efficient.
23:01 03-05-2012
Hallo! I am intrigued by the concept of an animal turning "inside out" to move based on the Festo's floater.
I was thinking if this is the only "design" that works this way, or if it would work with either more or less "segments" in the game. Is the machine the "middle way" of having just enough "segments" to work right and allow for a smooth movement while not having a needless ammount of failure points (joints)?
Also, I was also wondering if the present shape of the "segments" is the only one that works a "vertical" joint on one end and "vertical" joint on the other end of an individual segment... I was also thinking if a ring with triangular fins starting in the middle of the ring and probably even filling the entire inside of the ring couldn't do just the same, pushing the animal forwards by turning around.

Also, If I stay closer to the original shape, is the "four assembled triangular faces" a nexessary shape, or would a "twisted rectangle" (Like if you take a long ruler and twist it so the surfaces are horizontal on one end but vertical on the other).

On a totally unrelated note,  could a mechanical floater move like this "origami kaleidoscope:" - by pushing on the fluid by its many surfaces? Such a "multi-facetted" shape might not be a plausible one for an animal, but it still makes me wonder...

Those are my thoughts and ideas, I don't deman an answer, but It would be cool to see your opinions on this.
14:03 30-04-2012
The Festo solution seems to be exactly what Thomastapir had in mind. I wonder whether it would work with a torus, as I mentioned earlier. The points at the inside of the torus would lie on the outside after half a rotation (I cannot place images here, or I would post one to explain it with more ease). Adding flaps on the surface would provide it with an easy way to obtain propulsive force. All its tissues would have to be very elastic, though, so it would probably work better for a gelatinous jellfish-like organism than for a bone-and-muscle organism.  The question is why it would evolve this particular mode of locomotion instead of a more conventional one, probably easier to achieve.

Spugpow: I do not think that a reversible creature like that corresponds well to a jellyfish with a hollow in the middle: it would look like a ring, but would not go rotate around the circular toridal axis. Or was that what you meant?      
11:07 30-04-2012
It occurred to me while watching this video  that a reversible creature might be able to create toroidal vortices to carry it forward through the fluid medium. I don't know enough about fluid dynamics to say whether that would work or not.
10:52 30-04-2012
I don't think it's too hard to justify a biological version in the water. A its most basic, it's really just a jellyfish with a centrally placed hole in the bell (it might even have greater propulsive efficiency than a jellyfish due to its flow-thru design).
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