Fun With One Cut

Inspired by a brilliant talk by Erik Demaine, I started playing around with the famous one-cut problem:  given a shape made up of straight line segments, can you fold the paper flat in such a way that with only one straight cut your shape will appear?

Having no real experience with mathematical paper folding, I thought I’d try out a Koch Curve.  Well, a finite iteration of it, at least.

Koch 1

It seemed like the strategy was to use the symmetry of the shape to make all the line segments line up on each other.  So I folded down the middle, and then again down the new middle.

One-Cut Collage 1

 

I rotated the last shape and it seemed a little clearer how to continue.

One-Cut Collage 2

It seemed like all the lines were lined up, so to speak.  So I cut.  And voila!

Koch 2

Not too bad!  Now, if I could just figure out how to do this with non-symmetric figures.

Related Posts

Rock, Paper, Scissors

NYT rock paper scissorsThis is a great interactive Rock-Paper-Scissors game from the New York Times website:

http://www.nytimes.com/interactive/science/rock-paper-scissors.html

The computer will narrate its strategy for you as you play, telling you whether it has correctly predicted your choice or not.

Skeptical?  Play the game against the Veteran computer and watch it beat you!  Then, go check out this infographic for some tips on how to improve your play.

It might be fun to pit a 6-sided die against the computer to see what happens.

Another Mechanical Calculator

odhner mechanical calculatorThis video demonstrates the Original Odhner mechanical calculator.

http://www.youtube.com/watch?v=Bz8_tNDUDog

It looks like a miniature typewriter, and it seems to operate in the same manner as the Curta mechanical calculator:  switches allow you to “input” numbers into the machine, and then turning a crank performs addition or subtraction.

The video demonstrates some basic operations of the Odhner, and it includes  a nice (if lengthy) computation of the square root of 2 that involves a few arithmetic tricks.

More Math Careers

we do mathThis is an excellent collection of profiles of people who use serious mathematics in their careers:

http://www.maa.org/careers/profiles.html

This resources from the Mathematical Association of America (MAA) profiles over one hundred individuals whose careers span Actuary Science, Engineering, Systems Analysis, Computing, Law, and Academia.  Each profile includes a personal statement from the individual in which they describe the fundamental role mathematics plays in their lives and careers.

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