Math and Art: The Art of the Ellipse

This is a cool article about how important the ellipse is to the artist.

http://opinionator.blogs.nytimes.com/2010/09/23/the-frisbee-of-art/

The author gives a nice, if long, explanation about the significance of the ellipse, but it basically boils down to this:  circles are everywhere. And often, when we are looking at circles, we’re looking at them atilt.  We see projections of the circle, and projections of circles are ellipses.

Think of it this way:  suppose you have a hula hoop and you hold it parallel to the ground.  The shadow you see is circular, but if you tilt the hula hoop, the shadow will change–into an ellipse.  I don’t have a hula hoop, so I made do with a spare key ring:

As the circular key ring is rotated, it becomes less parallel to the ground; the shadow becomes less circular and more elliptical.  And at the end, the ellipse vanishes–an ellipse eclipse!

Math and Art: Bridges 2011, Coimbra

In honor of the Bridges Organization and its annual conference on Math and Art,  I will be posting about math, art, and their many intersections for the next two weeks.

The Bridges 2011 conference, held in Coimbra, Portugal, features prominent mathematicians and artists from around the world.  Fields’ Medalist William Thurston and the soon-to-be Museum of Mathematics‘ George Hart among others will be giving talks and presenting their art.  A program of select participants can be seen here:

http://bridgesmathart.org/bridges-2011/2011-speakers-coordinators/

A Tiny Triumph for Mathematical Consistency

Compared to most people, I have a heightened sense of math.  One of the ways this manifests itself is through discomfort with mathematical inconsistency.

For example, inconsistent menu pricing drives me crazy (like on this Wendy’s Menu), and consistent menu pricing leaves me with a warm, fuzzy feeling (like on this Five Guys’ Menu).  A recent example of this mathematical discomfort occurred at a studio where I often play music.

The owner of the studio is liquidating his library of VHS Tapes, which include a lot of rare concert videos.  The tapes are nicely displayed in a glass case, and a sign displayed the prices:

I’m friendly with the staff, so I felt comfortable going off on a mathematical rant in front of them.  I started in on their pricing structure.

“These prices don’t make sense,” I said.  “If someone buys 4 tapes, the cost is $2.50 per tape; for 8 tapes, it’s still $2.50 per tape.  Shouldn’t you be offering a larger discount for 8 tapes?”

I continued.  “And look, if you buy 8 tapes, tapes 5, 6, 7,and 8 each cost $2.50, the same as tapes 1, 2, 3, and 4.  But if you buy 12 tapes, tapes 9, 10, 11, and 12 each cost $1.25!  The marginal cost of a tape should be strictly decreasing!”

The staff humored me by sharing a laugh over my mathematical discomfort, and that was the end of it.  Until I returned to the studio.

As I was packing up and checking out of my session, a staffer approached me.  “I thought about what you said last time; it made a lot of sense.”  I responded with a quizzical look, unsure of what he was talking about.  “The cost of the tapes,” he said.  He pointed to the glass case.  “I changed the pricing system because of you.”

I slept a little easier that night, knowing that I had struck a blow for mathematical consistency.

Yet Another Car Rental Scam

As a car-less person in a car-driven world, I occasionally need to rent a car to move sofas, bring home large plants, or just get away from all my car-less neighbors for the weekend.  A long history of distrust of car-related business people (sales, repair) makes me approach my car-rental interactions with cynicism.  Here’s yet another reason that cynicism is justified.

Car rental agencies offer a Pre-Pay for Gas option when you pick up your vehicle.  “Pay now, and you won’t have to worry about filling the tank when you return the car.  It’s less hassle for you! ” says the salesperson.  “You even get a discounted rate on gas!”  It’s not emphasized initially, but you won’t be charged what it costs to fill the tank when you return the car; you will be charged for a full tank of gas, regardless of how much gas is in the tank.

This is actually a good deal for you if you can arrange your travel in such a way as to roll into the lot on an empty tank of gas.  But if you pre-pay and then return the car with half a tank of fuel?  You just gave the rental agency 8 gallons X $4 per gallon = $32 worth of gas.  That’s a nice little bonus for them!

And for the record, the sort of meticulous, obsessive planning required to return a rental car on empty tends to detract from the fun of your road-trip.  Not for me, necessarily, but potentially for your passengers.

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