[This article was first published on Revolutions, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)

---

Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.

I finally got the new version of Twitter yesterday, and it looks great. And that's no accident: according to the designer, the layout of the new Twitter interface is based on the Golden Spiral:

You can describe the Golden Spiral by laying consecutive squares in a spiral fashion, each square being smaller than the last by a factor of the Golden Ratio, (1+sqrt(5))/2 or approximately 1.618. As a ratio of a length to a width, the Golden Ratio has been known by artists for millenia as an aesthetically pleasing aspect ratio for rectangular features in works of art (such as the dimensions of a painting). It's also known to mathematicians and statisticians as the number to which ratios of successive members of the Fibonacci sequence converge.

In a classic case of using a sledgehammer to crack a walnut, I created a custom iterator in R to represent the Fibonacci sequence (code after the fold) and verified the ratio converges to the Golden Ratio at the R command line:

> fib1 <- iFib(); nextElem(fib1)
[1] 1
> fib2 <- iFib()
> nextElem(fib1)/nextElem(fib2)
[1] 1
> nextElem(fib1)/nextElem(fib2)
[1] 2
> nextElem(fib1)/nextElem(fib2)
[1] 1.5
> nextElem(fib1)/nextElem(fib2)
[1] 1.666667
> nextElem(fib1)/nextElem(fib2)
[1] 1.6
> nextElem(fib1)/nextElem(fib2)
[1] 1.625
> nextElem(fib1)/nextElem(fib2)
[1] 1.615385
> nextElem(fib1)/nextElem(fib2)
[1] 1.619048
> nextElem(fib1)/nextElem(fib2)
[1] 1.617647
> nextElem(fib1)/nextElem(fib2)
[1] 1.618182
> nextElem(fib1)/nextElem(fib2)
[1] 1.617978
> nextElem(fib1)/nextElem(fib2)
[1] 1.618056
> nextElem(fib1)/nextElem(fib2)
[1] 1.618026

See? Golden ratio.

Twitter: @stop

require(iterators)
## Generator for Fibonacci sequence
iFib <- function() {
	lastFib <- 0
	nextFib <- 1
	nextEl <- function() {
		newLast <<- nextFib
		nextFib <<- lastFib + nextFib
  lastFib <<- newLast
  lastFib
	}
	it <- list(nextElem = nextEl)
	class(it) <- c('abstractiter','iter')
	it
}

---

R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.

---

Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.