A call for community supplied Julia Code Examples

The default example (Code examples) Mandelbrot set can be written cheaper:

f(z,a) = z^2 + a
mandelbrot(a, n=50) = (n == 0) ? 0 : f(mandelbrot(a, n-1) ,a)

or even

mandelbrot(a, n=50) = (n == 0) ? 0 : mandelbrot(a, n-1)^2 + a

Instead of

function mandelbrot(a)
    z = 0
    for i=1:50
        z = z^2 + a
    end
    return z
end