[R] A little complex puzzle

[Bill.Venables at csiro.au]

I was looking for an example of complex variables in R.  This one is trivial, but rather cute (though World War II aficionados may 'come over all funny').

See if you can guess the image before you try the function.  It's not difficult.

jif <- function(res = 100) {
  z <- sample(do.call(complex, subset(expand.grid(real =
                                                  seq(-3, 4, len = 7*res + 1), 
                                                  imaginary =
                                                  seq(-2, 2, len = 4*res + 1)),
                                      real > -2.439 & real < 3.717)))
  del <- 2*base::pi/32
  plot(z, type = "n", asp = 1, ann = FALSE, axes = FALSE)
  points(z[((Arg(z) + del/2) %/% del) %% 2 == 0
           | Mod(z) < 1.15], col = "red", pch = ".")
}

Njoi.

Bill Venables.