Eleven Days in May

Amidst all the hype surrounding the coronavirus, I thought it would be useful to find some perspective on how bad it really is. One of the big problems with the reporting is that everyone seems to have a different way to count who actually died of it, or who got it and died for some some other reason.
One good way to finesse the issue is simply to look at the numbers of people who died from any reason at all, and see if that is significantly different from before the virus got loose.
There is a very informative page at the CDC website which lists exactly that.
Here is the graph it shows for the past few years:

Note several things it shows you: on an average, about 56,000 Americans die every week. There is an annual cycle that varies this by about 10%. The statistically significant border, (orange line) is about 2000 higher than the average; what that means is that variations lower than the line are to be expected and shouldn't be interpreted as proving anything.
Back in the winter of '18 we had a bad flu season and deaths broke through the line for about a month. We can compare that to the current peak and say several things. First, the coronavirus is definitely worse than even a bad flu season. But it's a judgement call whether it's enough worse to be considered a qualitatively different thing.
Second, the effect of the virus is very different from place to place. Here is New York City (you can call up all these from the page):



Yikes. The virus was an unmitigated disaster there. But look at, say, North Carolina:







There is no discernible impact from the virus at all. (Note that the falloff in the last few weeks, in all the graphs, is not real and an artifact of reporting lag.)

So what does this all mean? Raw numbers of deaths need a bit of perspective themselves. Here's a graph of how long you can expect to live as an American:


It works like this: God picks a point for you on the left axis, and you extend a line out horizontally until you hit the curve, at which point you die.
It turns out that given the numbers above, we can calculate where the curve would be given the coronavirus. In fact, I have done so, and the results are shown in the red line on the above graph. Can't see it? Neither can I; it's only 11 days shorter than the original black one. You have to zoom in to a scale of a couple of years even to see the difference:



The best way to think about the virus for the US population as a whole is that it has cost each of us 11 days of life. For most of us, that's in the noise. If you are in New York, or way out to the right side nearing the curve, it looms larger.

The spherical 5-bar linkage

I've been working on one, and amused to find that the physical construction and control software took about the same amount of time. Here's a movie, under control of the mouse in the other hand:

The idea of a spherical linkage is that all the motion takes place on the surface of an imaginary sphere, but in reality the links can be at different radii as long as their motion is well-described by rigid shapes moving on the sphere.  That makes it possible to construct in the real world.
There's some fairly cute math involved in converting a position you want the end axis to be, to angles to set the driving servos.  Quaternions are involved.