Judge's collar tessellation

In the Storsalen in Trondheim Rådhuset (Trondheim City Hall). This piece of wall art is made from the collars that judges used to wear as part of their costume. The collars are connected by folding them naturally into y-shapes and buttoning them together to make hexagons. Excellent use of discarded costume bits.

3d moving ball surface

Here's a very cool piece of ceiling art at one of the Olympics building in Beijing. This video was taken by my friend Nils Kristian Rossing.

Sizing your skis

I was trying to find some info on sizing my daughter's skis. Here's some interesting sizing advice from an article at ehow.com, January 2012:

See the problem with the formula? Multiply your height by 2.6 and then divide by 25 to find your ski length. Or, just divide your height by 10 essentially. I'm 6'1", or 73 inches, so my skis should be 7 inches long. That's nice, I can fit them in my pocket. No more struggling to get them into the car. Unfortunately, my ski boots are twice that length, so I'm not sure I'm going to attach the bindings.

I found the original article at Ski Post, and they write:

"For Traditional length classical skis (Your height in inches) x 2.6 + 15 inches = approximate ski length in cm."

There's still conversion and unit issues here. Better:

(Your height in inches) x 2.54 cm/in + 15 cm = approximate ski lenghth.

Or how about just: Your height + four to twelve inches?

11^6

Where were you 11/11/11 at 11:11:11? Here's me at the moment, in the minibus.

 

One of my former students in Washington used to always make a wish at 11:11. I just heard that this time, as she was making her wish, her boyfriend ran into the room with a ring saying his wish was to spend the rest of his life with her. Awesome! Congratulations L.Z.!

Mathematical Aesthetics in a Beautiful Town

One of my works from the 2011 Bridges Mathematical Art Conference in Coimbra Portugal made it into the Notice of the AMS. Here's a link to the article and a screen shot of one of the pages.

www.ams.org/notices/201205/rtx120500648p.pdf

xkcd puzzle

Here's a fun calculation from xkcd.com. Puzzle: why does this work? Can you find other numbers in which the same trick applies? Can you generalize?

Prime number chemistry

It's Forskningsdagene, or Research Days, in Norway. Many big cities have special events to celebrate science research. In Trondheim there are series of shows and lectures and the Research "Torg" (market/square/court?) Every year, the math center participates in the torg, and for the past few years I've been in charge of planning and coordinating the event with the university's math department.

The theme for this year was chemistry, so we decided to 'number chemistry'. I've always thought of the integers like molecules, with prime numbers as the atoms. We set up number molecule decorations, a prime number target game, and computers where visitors could find the prime factorizations of their phone numbers.

Students for the math department made the decorations and the ball toss game and did a very nice job. I wrote the program to find the factorizations, and we all made a variety of signs talking about primes, twin primes, the GIMPS project, and some prime number periodic tables that are pretty cool.

The game was a big success. Kids waiting in line were given a card with a number on it, maybe 18 or 54 or 770. The would need to figure out the prime factors by the time they got to the front. They would then throw balls at targets painted with primes, the goal being to knock down primes whose product matched the target number. Winners wrote their names on a sticky note and stuck it on the wall, enough of reward to make players proud without having to hand out candy.

Here's my periodic table of prime numbers, made to match the chemistry theme of the day and drive home the idea of "primes as atoms". Twin primes are colored gray, with symbols added for Mersenne primes, Sophie Germaine primes, Fermat primes, and palindrome primes. I think it came out nice!

I went through many iterations of the table. I harbored an unfounded hope that maybe by organizing the integers in a different form maybe some kind of cool pattern would pop out. Here's the periodic table shape with integers starting at 1 and all of the prime numbers colored blue. It turns out that even in the periodic table format, the primes appear to be patternless. I don't know whether to be happy or sad.