## Monday, August 22, 2016

### No more than eight times?

No more than eight times?  Have you ever heard the claim that it's impossible to fold a piece of paper in half more than eight times?  Allegedly it doesn't matter how big the paper is, how thin, or anything else.  I read that somewhere years ago, and dismissed it as nonsense with a simple thought experiment: if I took a long enough piece of paper, clearly I could fold it in half 9 times (at least).  For example, just to make the math easy, imagine that I had a piece of paper that was 1 meter wide by 512 meters long, and 0.1 mm thick.  Folded in half 9 times in the long direction, I'd have 512 layers, or 51.2 mm of paper thickness, each of these pieces roughly 1 meter square.  For you non-metric folks, that's roughly 2 inches thick by a yard square.

So with that thought experiment, I dismissed the claim as complete nonsense.

This morning I ran across a reference to a young woman (Britney Gallivan) who rather more formally debunked the claim.  That's her at right, with a piece of paper folded 11 times.  I'd not heard of her and her work before.  It's delightful!  Here are a couple of stories about it.  Even better, now if you search for "can't fold paper in half more than", you'll get all sorts of references to her paper.  She's famous, to a certain set of geeky folks.  :)