I Did It!

• Woooo! On 03/26/2007 I started at 259. Today I'm at 199.

  That's right, just 1/2 lb per week. Slow and steady catches the worm. In graphical form:

  My BMI is still technically overweight, though. Granted, BMI isn't a very good measure, but in this case I agree with the assessment and I'm going to go for 10 more lbs.



• I've only recently started using multiple colors of clay together. I have an irrational fear of "using up" the clay when I mix it, even though a pound of clay is like $1. However, a clay model gathers impossible-to-remove dust and small nicks. So I've finally bitten the more expensive bullet of switching to sculpey.

  A 4 year old of my acquaintance calls this "the treasure cat" and a 2 year old, also of my acquaintance, calls it "measure cat". (Also, any Cheshire Experts will notice right away the wrong color I didn't notice until too late.)



• I have a scrollsaw from way back but the blade broke and it turns out that that size is hard to find. Then last weekend I found a bandsaw at the flea market! After some tuning and tweaking, it's running great.

  Is this

  the first step on the road to this?

  Doubtful. But maybe!

I Just Won The Nobel Prize In Sandwiches

A BLT, only instead of mayonnaise, guacamole.

I wonder if egg salad could also benefit.

Contributing to the NERDliness of a Minor

Two minors, actually. A few months ago, I caved in to demands of my oldest two boys (10 and 8) to play D&D. They made me be the DM and they loved it. I did not really love it for several reasons:

1. Never played before. Any halfway game is annoying the first few times as you learn The System and what is and isn't important, etc.
2. Takes a lot of time to set up.
3. I feel like a real dork saying things like "leathern helm" or "dwarf mage".

So I didn't do it again. But that didn't make the demands stop. Finally, I told the 10 year old that I would play with them if he was the DM. Last night, we started that game.

Which brings me to the nerdliness. Playing D&D. Around the dining room table. While eating pizza, hot dogs and nachos. At least none of us has a neckbeard or obesity problem. Although one of us runs Linux. Oh and Mom brought in a sugary snack, plus we had our first game-based injoke.

Anyway, he actually did really, really well at it. I mean, we're wandering around without a clue in a very haphazard dungeon and he's giving hints pretty often ("do you want to check behind you?")...but he has the right attitude. He's confidently telling us what's what and taking our unanticipated actions completely in stride. Kudos, proto-NERD!

Happy Modification Of Most Sigificant Digit In Base 10 Representation Day!

I didn't even think to comment when the MSB in base 2 changed. What kind of a NERD am I?

Once my average catches up with the daily weigh-in, I'll be Officially At My (Original) Goal. I think I'm going to aim at another 10 lbs, though.

In other news, I've been messing around with Haskell, but I need a real programming project to really do something. I was thinking about this again.

I realized yesterday that it's not just hard but actually logically impossible to represent a mechanical object physically as a strict tree. Consider even just a triangle of beams. Two of them attach, making them children of the same parent (the joint). The third attaches to both, which is illegal.

A commenter suggested the netlist approach that electronic simulators take. The problem is that the netlist is a genome of the device. I have to be able to take a subset of the genome and swap it out for another piece that also has to drop in place. How does that work without leaving dangling "wires"? I could just leave them there for Nature to work out, but is that going to make success too infrequent for me to have patience for?

I think my algorithmic approach could work. But I haven't really worked it out. In any case, Haskell (or possibly better yet, Tcl or Lisp) is probably a good match. These languages already allow you to run data as code and treat code like data easily. Actually, now that I think about it, I'm not sure Haskell does that. What is that property even called?

Potpourri

• Continuing an Obsolete Technology theme from my last entry, I got a mechanical alarm clock at the flea market. All the parts worked, but it lost 5-10 minutes over a 12 hour period, at which point it would stop.

  I got a couple old-timey clock repair books at the library for tips on what to clean and/or adjust. Now it actually gains 2-3 minutes in 24 hours, but I recentered the little adjusty lever, so I should be able to make it keep good time. Unfortunately it still alarms 10 minutes before the set time. Also, it sounds like a fire alarm, which is maybe not the ideal thing to wake up only a single person at 5:30 am.

• Could have used this site years ago. Or is there a way to put MathML on Blogger now? If not, I guess I should learn LaTeX.

  

• While looking forward to LogiComix, I came across Uncle Petros and the Goldbach Conjecture. Fun, short read. I already knew about the Goldbach Conjecture, but the book gave me an idea for a possible disproof that probably doesn't work. First, the Conjecture: All even numbers > 2 can be expressed as the sum of two primes. One way to disprove this would be to find a number n such that no numbers from n to 2n are prime. There is already a theorem that proves that you can construct a "prime gap" of any size, so one of length n is no problem. The reason this doesn't quite work is that you also have to specify that the gap starts at n. Oh wait, it's even worse than that. There's a prime between n and 2n for all n. Pffff.
• You know what would be a killer app? Online WINE/Crossover. I could upload a Windows/OSX app and install it on a virtual machine and then interact with it via a generated Flash interface. I guess the only really hard part of this is the "generated Flash interface". Kind of like those programs that let me display on another computer (like X-Windows, but for all OSes) where the "another computer" is "a Flash app".

Two Unrelated Things

Just finished reading The Swiss Family Robinson. Two main things jumped out at me.

1. An incredible quantity of animals are killed. It's seriously like every couple of pages they take down a kangaroo, shoot an agouti or chop a snake. After the fact they talk a lot about the "magnificent creature" but beforehand they don't think twice. They don't even know what most of the animals even are and they start shooting. (They also have an unending supply of ammo.)

   The irony of the family often being afraid of "savages" in this context is pretty thick.

   The variety of animals is also pretty astonishing (which is to say fictional). On what island exactly do monkeys, wild hogs, buffalo, kangaroos, lions, boa constrictors and ostriches all coincide?

2. There are many similarities to Robinson Crusoe. I noticed them at the time but can't think of any now, so I'm left with the obvious statement that they are both shipwrecked on an island.

   Anyway, in the text they mention that they are Swiss (duh) and don't speak English (whoa!). Looking it up afterwards, it turns out that "Swiss Family Robinson" is kind of a misnomer. They aren't named Robinson. In fact, their name is never given, only the 4 sons are addressed by names with the man being the narrator and the wife called "the wife" or "the mother". The real translation of the original title is more like "The Swiss Robinsons" as in "a Swiss version of the Robinson Crusoe".

   Also, especially near the end, there were many similarities with some of the Heinlein juveniles. I think RAH even said he'd "filed the serial numbers off" of SFR a couple times. Knowing the actual plot of the original now, I should reread the juveniles.

The other thing is slide rules. I asked Freecycle for a slide rule and a kind soul gave me 3. All 3 in leather cases, one of them bamboo and new in box. Wow.

One
Two
Three (has 23 scales on it!)

I feel like such a retro-nerd messing around with them, although I can barely do even simple problems. You really get a sense of what a chore basic computation used to be if this slow, error-prone, laborious process was the easy way.

Modulo Operator Considered Harmful

The way I think of the modulo operator is as a remainder. 10 mod 3 = 1, because 3 * 3 = 9 and 10 - 9 = 1. But what if one of the operands is negative? What is -10 mod 3?

My naive answer was that this is obvious. -10/3 = -3. -3 * 3 = -9. To get from -9 to -10, you need to add -1. Therefore the remainder is -1. Let's see what C thinks of that:

#include 

int main(void) {
  printf(" 10 mod  3 = %d\n", 10%3);
  printf("-10 mod  3 = %d\n", -10%3);
  printf(" 10 mod -3 = %d\n", 10%-3);
  printf("-10 mod -3 = %d\n", -10%-3);

  return 0;
}

$ gcc -o mod mod.c
$ ./mod
 10 mod  3 = 1
-10 mod  3 = -1
 10 mod -3 = 1
-10 mod -3 = -1

C agrees! And I'm sure Python must follow, right?

#!/usr/bin/env python

print " 10 mod  3 = ", 10 % 3
print "-10 mod  3 = ", -10 % 3
print " 10 mod -3 = ", 10 % -3
print "-10 mod -3 = ", -10 % -3

$ ./mod.py
 10 mod  3 =  1
-10 mod  3 =  2
 10 mod -3 =  -2
-10 mod -3 =  -1

2?!?!

There's a couple ways to look at this. First, what really is the answer of -10/3 in integer division? The "real" answer (seewhatididthere) is -3.333.... When I round that to an integer, do I round "down" meaning "to the left on the number line" or "down" meaning "towards zero"? If I mean the latter, -10/3 = -3. But if I mean the first meaning, then -10/3 = -4. Then 3*-4 = -12 and so the remainder is actually 2. (If you ask Python what -10/3 is, you do in fact get -4, btw.)

Alternatively, I could revert to doing modular arithmetic under it's old name of "clock arithmetic". For 10 mod 3, the face has 3 numbers and I'm going to take 10 steps around it, starting at 0 and moving clockwise. I end up on 1. For -10 mod 3, I'm going to go counterclockwise. I end up on 2.

To me, this second interpretation is better. For one thing, rounding leftwards seems to be as counterintuitive as the original problem. For another, this clock method explains what a 10 % -3 should be. The clock face contains the space of possible answers. Doing mod 3, the answers can only be 0, 1 or 2. Doing mod -3, the answers can only be 0, -1 and -2.

Wikipedia agrees with Python, which seems to leave C out in the cold. Its folk understanding of modulo as remainder is common sense but wrong. And it isn't alone. (Some languages have mod vs rem, with the latter being a remainder. That's a good idea. Naturally FORTRAN has called the two operators mod and modulo. Stay classy, FORTRAN.)

However, it is still true that if you are working only with positive numbers, mod is a remainder. Because of this intuitive understanding, and because of the obvious confusion among language designers, it seems a good idea to me to always frame mod operations in positive space.

Infocard: Useful Knots

I often need knots. I have often learned the knots I need. But these two things never happen close enough together to result in long term knowledge storage. This Make blog post gave me the idea of collecting a few useful ones and putting them on wallet card.

Front:

Back:

Printed front and back on a business card and then laminated, it can nestle in my wallet until I need them. Alternatively, for this particular application, I could secret cards in amongst any ropes I might use so they are johnny-on-the-spot at the right moment.

And speaking of applications, I was also thinking this could be a neat idea for other things. How to mix drinks, electronics cheatsheet, math formulae, What To Do If Arrested, etc. In fact, it seems like such an obvious idea I spent some time googling to see if anyone had set up a Web 2.0 social networking site to do this. Nothing. So I hereafter document my process for my future self and anyone else who wants to make one:

1. Design it up a bit. In this case, I tried to pick some knots that were both unlike each other and also widely useful. There's a loop, a general "tie to a post", a stopper that can also make a second type of loop and finally a bend, which is a knot that attaches two ropes. I also wanted a "scenario" that would tie it all together (ha!). And it all has to fit on a business card.


2. Once the contents were identified, I drew all the images with pencil. I actually first started with some copyright-free knot images from a Project Gutenberg book, but there were a few problems with that. The main one was that not all the knots I wanted had drawings. Also, the images were too busy to be shrunk down that small.


3. Trace with pen. May not have been strictly necessary, but didn't take too much time anyway. Scan. Load into Gimp and fix any boo-boos. Smudges, pen dropouts, etc. With a cheap graphics tablet, I could have skipped a lot of this.


4. Bring into Inkscape and auto-trace bitmap into a vector format.


5. Use Scribus to lay out the page.


6. Print onto business card template thingies. Get laminated.

If this were an online service or community or whatevs, there would be PDFs and/or inkscape/scribus files. However, I don't have a way to host anything but images here. Suggestions?

Artistic Voice, And Poundage, Being Suppressed

You may remember my previous, paradigm-shifting, boundary-pushing art installation. A chance remark from a coworker caused me to think of another. No pictures, sadly, and it only lasted about an hour.

The idea was: The cubbies kind of look like a vertical cross section of an apartment building. So I filled them with doll furniture to simulate different apartments. One had a bed, another a lamp and armchair, another a toilet and sink, etc. There was room for the cellphones to perch on the "floor" but I really intended the phones to live in the apartments--sleep in the beds, sit in the chairs, etc.

Sadly, some humorless nitwit removed it all because some VIPs are coming through. And we all know VIPs will instantly be turned to powder if they crack a smile. (The VIPs canceled a few minutes later, but now I shan't share. Or maybe I will.)

Unrelatedly, my birthday has come and gone and I didn't quite meet the goal of -60 lbs. However, I'm exactly 3.5 lbs short of it and closing fast, so I'm not too disappointed. What's weird is that the stupid Wii doesn't seem to notice. I deliberately wear exactly the same clothes every time I weigh in and have lost at least 2 lbs since it started tracking me, but no. Then again, it cares more about BMI which changes less rapidly than lbs (they are both linear, but I mean numerically).

They'll Have Nothing To Lose But Their Chaindrives (Invention Idea #5)

Why do I have to have a job? There are basically four reasons: Food, shelter, medical care and luxuries.

Those are listed in rough order of importance. Theoretically an order-of-importance list is also an order-of-most-money-spent list but that's probably not literally true. However, from the point of view of reducing costs, it kind of is. $500 that I must spend on food is a tougher nut to a short budget than $2000 that I throw away on bingo. Put another way: Say I wanted to stop working. What's the first problem I absolutely must solve? It isn't "where am I gonna get my $2000 of bingo money". It's "how do I eat".

So how would I eat? One common solution is to start your own business. But that's still a job, albeit one where you are the boss. I'm imagining a socialist utopia where nobody would have to do any work at all. We'd just recline on chaise lounges all day.

I could grow my own food in my yard. That's still a lot of work, though. Planting, weeding, chasing away predators, harvesting, processing, etc. However, this is all repetitive, physical work, which is perfect for whom? Robots!

The first thing you need is a big field. (You could do this in your yard, but for reasons of efficiency and scale, farm-like installations are probably better.). Enclose the entire thing in glass (height determined by the crop) to make it a greenhouse. This also excludes many, but not all, bugs, animals and weedseeds.

Install some sprinklers. You'll be using a lot less water than usual for two reasons. One is that because the field is enclosed it will lose less to evaporation from the ground or respiration from the plants. The other is that you can collect any runoff and reuse it. (Why don't they already do this? Maybe it seeps down to the groundwater first? Perhaps my field should be enclosed on the bottom, too.)

Send in the seedbots to do the planting. Seeds and the planting thereof are relatively uniform, so this is a general robot. We may need to bury guide cables underground that will indicate to the robot where the rows will be. However, optical guides, GPS or other technologies could also be used.

All of this, btw, is controlled by computer. It could either be a hulking 1950s-style centralized FARMIVAC thing or an ultra-modern distributed intelligence ant-model thing. For instance the seedbots detect that it's planting time, the sprinklers detect moisture levels, etc and everything Just Works kind of like a natural ecosystem.

Now is the somewhat harder, more nebulous part of my vision. Each growing plant species needs different care. Some might have to be checked for mold, some might need petting or to be sung to or whatever. And they are all harvested differently. You can just cut down cornstalks but you have to pick apples. All this variation means different robot types. That said, this isn't an insoluble problem.

Another option is trained monkeys.

(I googled around for a bit and found some talk about robot or automated farming, but there didn't seem to be any cohesive vision or big plans. In all seriousness, it seems like this is a major lack. Growing food is an absolutely necessary, but peasant-level job. Until robots do it, peasants will remain.)