Hexayurts and African Villages

April 23, 2010

As you may have guessed I am a fan of mathematics. Numbers themselves leave me cold, however. Even some of the great quests of modern mathematics can occasionally appear to me simply as sudoku for geniuses. The thing that gets me excited about mathematics is the way of thought. The way a simple proof can take a very difficult question, twist it and make it easy. The way you can take an idea and reduce it to its simplest possible form. Trying to find the smallest amount of structure one needs without the idea falling apart.

This process often takes you into incredibly abstract theoretical worlds. Yet by thinking in these terms we can often find ideas that were drowned out in complexity of the “real” world. One of my favourite examples of this is the fractal patterns found in African villages by Ron Eglash:

Aerial photo of Ba-ila settlement, before 1944. American Geographic Institute.

Once pointed out the ideas are not hard to see, and have been used to help understand the cultures the buildings come from, yet without the right idea of what to look for the structure is not obvious.

This example comes as much from anthropology as mathematics and it can often be easiest to describe what I feel is mathematical thought away from mathematics. My second example, therefore, comes from engineering. Consider a disaster like Haiti, infrastructure and housing have been destroyed. There is a need to quickly create shelter for a large number of people. The standard answer is the relief tent. This is a very short term solution however. It solves the problem, but a tent may not have a long life. Say a year or two. By this time the attention of the world has drifted. A better idea is to find cheap, easy to assemble shelters, often called transitional housing.

Vinay Gupta took a different route, and I am going to accuse him of mathematical thought. He cut away all the needs a house had and thought just about the simplest way to make a structure. He was actually thinking about how to make an easy geodesic dome. The result was the hexayurt, a building made of 12 sheets of (internationally ubiquitous) 4′x8′ plywood:

This is a building that can be made on site without specialist parts (a hammer, saw, some off cuts of wood and the 12 sheets are all that is required). A building that is cheaper than the standard relief tent (just $100). It does not even need much skill, though a fair amount of man power is needed, this is the one thing that such disasters usually have in abundance. Furthermore it is easy to adapt the building. A room can be divided off with 3 additional sheets, a taller building can be made by using two sheets to make square walls, as hexagons the buildings can be easily clustered. In fact, taking advantage of this I could not help but combine the two examples, to make a fractal village of hexayurts:

In all this however we have to be careful, malign forces are watching our every move and we never know when they might pounce:


Lasering my Laptop

April 17, 2010

I finally got the courage together to put my laptop into my lasercutter. It worked!

If anyone is interested this was using a 25W Versalaser at 100% power, 10% speed, 1000ppi (three powers of ten together at last):

The detail looks good even close up

Just for kicks here is my paint box that went under some time ago:


My dream Royal Institution

April 16, 2010

I grew up with the Christmas lectures. They were as much part of christmas as the Turkey. The Royal Insititution was a place of magic. Yet, the swanky Mayfair location completely passed me by. Davy was a man who had made a lamp. Faraday had something to do with electricity. I had not heard of Bragg or Porter. The magic came instead from one man: Bill Coates1:

A figure in the shadows of the lectures, but always there if you knew where to look. The man responsible for scientific demonstrations beyond anything else in the world at that time (to my knowledge). The RI was a place of magic and it was clear that this came  from Coates’ almost mythical prep room.

When I got to visit and work in the prep room last year2 therefore, it was a dream come true. Yet a dream tinged with sadness. This was a space neglected by the redevelopment, still brilliantly staffed but with out of date facilities. In fact, worse than neglect, the facilities had been cut, the workshops in the basement taken away by the refurbishment.

The current debate3, like the priorities of the leadership in the redevelopment, does not seem to capture what made the RI great and unique. The prestige of the building has been pushed with the development of a fancy restaurant. The prestige of cutting edge science has been pushed with a new nano-technology group. The building of magical machines to demonstrate science has been left behind. The building is prestigious, but it is in Mayfair where there is no shortage of prestigious locations; many more prestigious and more experienced at hosting events. The science of the RI is great, its place in history is secure, yet today many places do cutting edge research; many far better funded. What about science communication and science machines? They certainly live as deep in the Institution’s bones. Faraday’s popular lectures, especially his Chemical History of the Candle, put the place on the map at the time, more even than his work on electricity. Twenty five years ago I would argue the RI was ahead of everyone else in the world. That is no longer the case. There has been recent great development in science communication, others have caught up with the RI. As an example the Centre for Life in Newcastle has a wonderful line in informative, exciting science and shows with meat that rival Faraday’s candle. It is however a far less crowded field, something the country desperately needs and the RI is well within the leading group.

The standard rebuttal to all arguments about the RI (for the last decade, maybe longer) is that you are trying to recapture the glory of the past, not moving towards the future. Perhaps you could say this here. Bill Coates was a completely unique individual and not someone who can ever be replaced. No one will be able to create traffic jams for a science event today like Faraday did. This is true, but I also think these are ideas which are only just getting started. Today there are worlds available that simply would not have been possible before, even to a genius like Coates. We have laser-cutters, 5-axis routers, even 3d printing. The ability to transform ideas into objects has increased beyond recognition, moving from a highly skilled job to a semi-skilled one, even a mathematician can do it. It is not even that expensive. The MIT FabLab project gets you a good set up of machines for just $50,000 (~£32,500). Even better the designs can be released for others to make. Many schools have these machines, or at least access to them, and there has been a recent explosion of Maker Faires, hackerspaces and FabLabs where people come together with the desire to build stuff.

Let me sum up with my personal dream, vision, reinvention for the RI. That is what everyone says the RI needs after all. A scientific fab lab. A space with open access to all UK scientists kitted out with a workshop and computer manufacturing machines. Anyone with vague ideas for sciencey things to build can come along and get support from the scientifically knowledgeable and technically skilled staff (that the RI already has). After all the standard PhD does not have a lot of practical training in manufacturing. This would be combined with the other expertise the staff of the RI have in abundance: science communication, the christmas lectures, shows, masterclasses. An RI like this would be a place of magic for me once more, even to my more cynical adult mind. Perhaps I am not the only one.


Footnotes

1 BACK TO POST
In 1986 Coates retired, but the magic continued in the hands of Bryson Gore and others.

2 BACK TO POST
I was making material for How do shapes fill space? my exhibit at the 2009 Royal Society Summer exhibition. The RI was one of the partners and provided workshop space.

3 BACK TO POST
The problems started with the weak financial situation revealed (but not completely caused) by the credit crunch. This has been combined with the fight between the council and Susan Greenfield the director they made redundant. She has not gone quietly, and is now suing for unfair dismissal. In addition her supporters organised a Special General Meeting to try to remove the council but failed. This has of course led to open season on visions and reinventions for the RI, that I am leaping on board. You can find a lot more with a Google or Google News search. This story will probably run for a while!


Socolar and Taylor’s aperiodic tile.

April 1, 2010

Almost the 3d monotile...

As regular readers know I have a love of incomplete or impossible quests.  One such quest that comes very close to my work is quest for an aperiodic tile. A shape that can tile the plane, but not periodically. In other words I can cover whatever area I like (the floor of the room or the Milky Way Galaxy) but the tiling will never be a single patch moved about by translations. A big development, a new tile from Joshua Socolar and Joan Taylor, is therefore very exciting, especially as the final answer is still illusive.

Penrose tiles

For a long time it was thought that even for collections of tiles could not force non-periodicity. Then in the 1960s work in logic revealed that they could and the study of aperiodic tilings began. Today the phenomena is still not very well understood. There are only a few known aperiodic sets of shapes with a small number of tiles (though if you let the number of tiles get large an infinite number of examples are known).  Even for the known examples, such as the famous Penrose tiling, the proof that the tiles cannot tile in any periodic manner involves simply putting shapes together and showing patches that can and cannot occur. The Penrose tiling obviously uses two tiles, which leaves the quest: can it be done with one? So we come to the new tile:

Socolar and Taylor

This tile can tile the plane, but not in any periodic manner. This is enforced just by the shape of the tile. The red lines above are not necessary, but reveal a little of the structure of the tilings:

Patch of tiling, the red lines show a little of the structure of the tiling. The single grey tile shows how the different pieces of the tile fit together with its neighbours.

As you can see from the patch above the tile forces the formation of a sort of Sierpinsky triangle. It is this structure, occuring at all scales, that ensures that the tilings produced cannot be periodic.

You might have noticed that the tile shown above is slightly unusual. It is made up of several disconnected parts. This leaves a question open, is there a connected aperiodic tile? I would like this as the current tile is hard to make on the laser cutter! A possible way to solve this problem is to use a third dimension, and this is what Socolar and Taylor do, giving the tile shown at the start of this post. We can take copies of this tile and build patches, again the hierarchical triangles appear (note that the tiles fit together at different levels):

Patch of tiling with the 3d monotile. Note how the tiles fit together at different levels.

The larger space allow information on the tile edges to cross, as you can see in this patch with one tile removed:

Patch of tiling with one tile removed to show internal structure.

This tile therefore, is connected and can lie in no periodic tilings of 3d. However this is not quite the whole story, although the tilings produced will never use a finite region translated around they will only be non-periodic in two directions.  In the third direction the tiling can be periodic.

For more details look at Socolar and Taylor’s paper and Joan Taylor’s original paper (complete with beautiful hand-drawn images). The story has also been covered by the MAKE blog and Technology Review. If you want to make your own images and even tiles I have put my tile models up on Thingiverse and also put the blender file online.


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