Mitt liv som Tobin

Last week was Mad Science Week, an event that's been in the planning all summer. The basic idea is to design and execute a Tobin-esque project in a week, using collective grad school power to do something interesting. Our project consisted of a musical instrument controlled by the power of light. What this translated to was a bicycle light, a webcam, and a software synthesizer. I'll try and get a video of it out at some point, but what's important isn't the project itself, but that we finally did something. A lot of my department is lots of talk and almost no action, so it's refreshing to move past that, and spend a week programming and hooking things up and being frustrated and figuring things out together. Working hard on a project I like is infinitely more rewarding than leisure. I'm crushed that I don't get to work on a project I like all the time.

• Berkeley Steamtunnels web page (1999)
• San Juan Capistrano Hot Springs web page (1999)
• Splorg Potato Cannon web page (1997)
• ... other stuff that's really best left to the bit bucket

The urban legend that a would-be thief can pencil down your Vehicle Identification Number (VIN) and directly have a key made (and hence drive away with your prized ride) seems to be false—at least in the case of a 1992 Volkswagen. The actual protocol involves disassembling the door to get at the lock, then reading a four digit key-code off of the tumbler (whose relationship with the VIN, if any, is generally unknown), from which you can then directly cut a key. I thank AAA for doing this for me. Suckers with more "modern" conveyances, on the other hand, must have their vehicles towed to the dealer, whom they must then pay upwards of a thousand dollars for a retrofit. On the other hand, any Mark II Volkswagen can be opened instantaneously by jamming a small flathead screwdriver through the body directly underneath the lock and then thrusting upward (which I learned the hard way); with similar ease, if I'm reading the schematics correctly, the vehicle may be hotwired by bridging terminals 30 and 50 in the fusebox. Counterintuitively, the finest loss-prevention mechanism I've come across has been to leave the windows open and the locks unlocked—replacing window glass costs more than anything that could be pried out of the car.

So, Google currently has a little promotion that involves a sort of puzzle hunt. The first puzzle, published on billboards and at googleblogatom is to find the first 10-digit prime number to occur in consecutive digits of e.

I tried to solve it using only standard unix programs, with the following pipeline:

cat e.2mil | delay_line 10 | factor | awk '$1=$2":" {print($2)}'

That pops out the right answer immediately...

e.2mil is a text file containing the first 2 million digits of e, and delay_line is a little C program that takes a stream of characters and whenever it receives a character after the ninth character, it outputs the previous ten characters seen. It would be much more satisfying if delay_line were implemented as a clever script and perhaps if e.2mil were generated somehow instead of with Mathematica or a Google search. (I know that there are faster ways to check primality than explicitly computing factors, but obviously this is quick enough...)

Two fun exercises on the side: download GNU coreutils and look at the sourcecode to factor to see how it works (it uses 'Wheel Factorization'), and compute the expected position of the first 10-digit prime in a random sequence of digits.

The second puzzle is to find what comes next in this sequence: 7182818284, 8182845904, 8747135266, 7427466391, _____ .

Further notes will appear on nibot_lab.