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Saturday, August 27, 2011

Wicked sailing day

20-25 mph winds, 8-10 foot waves, it was nuts. I took all these folks out (and also Ashley, who was somewhere else when we were taking the photo) . Towards the end it was getting a bit harrowing, in swells we couldn't see over, and they were breaking near the shore line. I did three runs out to the two mile buoy and back, with only a little break between, with two passenger each time. It went off with nary a mishap, despite having misriggged the mainsheet initially, getting stuck in irons at launch the second time, and having the waves (and really strong wind) screw up our tack the third.

I was on the water for probably two hours total, and it was exhausting. Gives me a feeling for how difficult crossing the lake would actually be. Though in that wind, we'd have been nearly half way there in the two hours I spent on the water!

Thursday, August 25, 2011

Trancendentalism

Transcendental functions are crazy. I tried applying the tangent function to the y vertex coordinates in my ring design (long story, kinda boring, basically amounts to me having only the most rudimentary understanding of what the tangent function does), and this is what results:


Its... less wearable. But more space-ship like.


Thursday, August 18, 2011

Ambigram for DRH

Inspired by xkcd.com/917







Monday, August 15, 2011

Beautiful Summer

Rachael and I have been soaking up as much beach as possible. Here she is displaying her captives after beating me in beach-chess (which is much like normal chess, except that it later fills your apartment with sand):

A little later on, my favorite cloud came by to get in a picture with us:

After that, we discovered a truly fantastic sandcastle that someone left out on the beach for us, the photo of which I can't seem to upload without it getting messed up:


Later still, we savored the true flavor of Chicago at Mustard's Last Stand:
But the lake isn't all fun and games, it can be formidable and furious:
Kevin told us to look wistful and that's what we managed. Kevin and Rachael and I were going to go sailing on that day (which was yesterday), and I was really excited about the wind forecast. I had seen earlier in the week that it was supposed to be 15-20mph out of the north, and it ended up being more like 25-30. I didn't realize that north and west winds make for really rough seas; the waves were 6-10 feet and coming in fast. As we were walking towards the beach I saw the whitecaps and had a pause, but I was still intent on going out. I talked to the guy at the sailing beach-house, and he advised strongly against it, there being a marine warning in effect (which means that only the coast guard will come rescue you). We saw this other 'cat on the beach; I figured we'd watch and see how they did, and if it looked fun I'd convince Rachael and Kevin to give it a shot.
The sailors were, according to a bystander, fairly experienced. They lasted about five minutes, capsized, turtled, ended up with the boat on the rocks and themselves out to sea getting rescued by the coast guard.

I couldn't initially figure out what the black metal pole hanging from the top of the sail was; I realized only much later that it was the broken top five feet of the mast. At any rate, I let myself be persuaded to forgo sailing that day. In retrospect, looking at the first picture, their travails may have been much less terrible had they had had a mast-float; it seems very silly to sail without one.

Kevin and I went out aboard the Pianissimo the day before, on much gentler seas.
It went very softly indeed, as only a fifteen ton fifty foot yacht can. I don't know what's with my expression in this picture. Looking stern, I suppose.
[added: no, the camera is looking stern.]

Speaking of rough weather, we had a big wind storm a while back, and this car on my street discovered the virtue of parking in a garage:
I saw this on my way to work with the tree on top of it and the owner looking at it agape. Its a lovely neighborhood we've got here, full of mature tree-lined streets and on-street parking.

Here's two more pretty things: Rachael with a Willow crown and some pressed orchids I put in a transparent frame for her:


Sadly this masterpiece didn't last; the color of the flowers faded and it got wet in a rainstorm, making it get all splotchy. I had written "I Love You" in oil on the rice paper in the bottom left corner; the thought was that I wanted to include a message but didn't want to overly distract from the flowers. I used too much oil and it became pretty illegible, but it ended up looking sortof like asian writing if you turn it sideways, which goes with the aesthetic.



Saturday, August 6, 2011

More interesting things!

I have, over the course of the winter, been forging a Ring of Power. I haven't discussed it here because I wanted to keep its great importance a secret, but now the cat's mostly out of the bag; you see, I'm having one made that fits my finger (the fourth from the thumb on the left hand) and one that fits Rachael's.

Here's a few screenshots of the (nearly final) computer model:





Its a mobius ring with a triangular crossection. Rachael had brought up the idea of having a mobius strip ring like this, but I wasn't a fan of how the curve isn't continuous. I figured a two sided strip with a continious curve wouln't result in a very wearable ring, but I figured one with three might be more so. I made a few models out of wax and clay years ago, and vaugely dreamed of having enough mathematical sophistication to construct it perfectly, and over the course of serveral months this winter and spring I finally worked it out. I experimented with a lot of stuff and eventually settled on some matrix transformation methods. Reading some stuff like this may have helped: Mobius ring

The great Belgian Dutch smiths at Shapeways have taken this excretion of my mindgrapes and turned it into a physical object!Actually, several of them. Above is the (nearly) latest draft prototype, made from plastic. I had a bunch made so that I could be sure of the sizing, each one a millimeter smaller than the one previous. It is, as I'm sure you're keen to notice, too thick to be a comfortable ring; a fact that I realized moments after I order this batch. The next batch of more wearable rings is currently hurtling though space aboard an aeroplane as we speak, I believe.

The previous incarnation of the Ring, which finished its long journey to me back in May, is here:


As you can see, this one is totally metal. Its made of silver, and I basically drew it in Sketchup. This was before I figured out all the mathemagic that's required to make it have smooth sides and make it easily realizable. The segmented versions took about five hours each for me to draw, with only sixteen segments. I saw the futility of my Sketchy-ways, and decided to take the plunge and write a program to render it with whatever variations I wanted.

And here it is! Its written in Matlab; I may at some point re-write it in something cooler.

%make mobius ring

num_segments = 360;
side_length = pi()/10;
circumradius = 1/2 * side_length *csc(pi()/3) ;
%circumfrence = 4.7; %5.1 results in 5.3 effectively
circumfrence = 5.0; %5.3 results in 5.5

inradius = 1/2 * side_length *cot(pi()/3);
radius = (circumfrence / (2 * pi))+circumradius;
% stretch=1.61803399; %phi
stretch=2.71828183; %e

starting_plane = [circumradius*sin(0/(180/pi())), circumradius*cos(0/(180/pi())), 0
circumradius*sin(120/(180/pi())), circumradius*cos(120/(180/pi())), 0
circumradius*sin(240/(180/pi())), circumradius*cos(240/(180/pi())), 0];
translation = zeros(3);
translation(:,1)=radius;
twist = 120;
theta_z = (twist / num_segments)/(180/pi());
theta_y = (360/num_segments)/(180/pi());
theta_yi= theta_y;
row = 4;
vertices=starting_plane+translation;
for i = 1:(num_segments)
theta_zi= i * theta_z;
Rz=[cos(theta_zi), -sin(theta_zi), 0
sin(theta_zi), cos(theta_zi), 0
0, 0, 1];
new_plane=starting_plane*Rz;
new_plane = new_plane + translation;
theta_yi= theta_yi + theta_y;
Ry= [cos(theta_yi), 0, sin(theta_yi)
0, 1, 0
-sin(theta_yi), 0, cos(theta_yi)];
new_plane = new_plane*Ry;
vertices((row:(row+2)),:)=new_plane;
row = row+3;
end

S = [1 0 0
0 stretch 0
0 0 1];
vertices = vertices * S;

connections = zeros(num_segments*3,3);
connections(:,1)=(1:num_segments*3)';
con_2 = connections;
con_3 = connections;
for i =1:num_segments*3;
con_2(i,3) = con_2(i,1)-1;
con_2(i,2) = con_2(i,1)+2;
end
for i =1:num_segments*3;
con_3(i,3) = con_3(i,1)+2;
con_3(i,2) = con_3(i,1)+3;
end
connections = cat(1,con_2, con_3);
connections = mod(connections, ((num_segments*3)));
num_connections = size(connections);
num_connections = num_connections(1);

row = 1;
normals=zeros((triangles_count),3);
for i = 1:(triangles_count/3)
a = vertices((connections(row)+1), :);
b = vertices((connections(row + 1)+1), :);
c = vertices((connections(row + 2)+1), :);
AB = [(b(1)-a(1)), (b(2)-a(2)), (b(3)-a(3))];
AC = [(c(1)-a(1)), (c(2)-a(2)), (c(3)-a(3))];
%do crossproduct;
n = cross(AB,AC);
for j = row:(row+3)
normals(j,:) = n;
end
row = row + 3;
end

plot3(vertices(:,1),vertices(:,2),vertices(:,3));
axis([-4 4 -4 4 -4 4]);

Debt Downgrade!

This morning, after returning from the farmer's market on my bicycle, I was shocked to open my paper-paper and find this news:


How I failed to become aware of this yesterday fairly boggles the mind. I had the radio on on the way home, and web-browsers open all day. I guess it was announced later? Or NPR didn't find it a fit subject of commentary?

Anyway, this is one eventuality that I never heard anyone discuss during the media charade around the debt ceiling. I heard lots of discussion about the horrors that await us in the form of a credit downgrade if we didn't raise the debt ceiling, but nary a mention of the possibility that we would be stricken with the same fate if we did.

It seems pretty obvious in retrospect. Can the United States, as a matter of fact, make good on all the promises its made? Absolutely not, and everyone who's been paying the slightest attention knows it. That the S&P should come out and say it was only a matter of time, and perhaps the biggest surprise is that it's taken this long. It's appalling the way people let political allegiance distract them from the facts of their environment.

Here's a thought: to whatever extent this actually changes investors' behavior (you could argue that the downgrade's been priced into the market for a long time), it should have the effect of making some private debt more comparable to US sovereign debt. Thus, investors should be more willing to substitute private debt for sovereign debt which means lending money to companies rather than governments. What effect does this have? Money that would otherwise be locked up in government projects will instead be allocated to private projects, which are inevitably more productive.

On the other hand, the government always has the power monetize the debt, something that I think its under-appreciated in its insidiousness.

Added: is that picture cropped that way on purpose?