maple plot of Belyi function

Question

I would like to understand how to construct Figure 5 of the paper Composition is a generalized symmetry by Alexander Zvonkin:

The hypermap/dessin d'enfant of Figure 4 is while the Belyi function (1) is defined by $$f(x) = \frac{50000}{27} \cdot \frac{x^6(x-1)^3(x+1)}{(x^2 + 4x - 1)^5}.$$

Now, I understand that the plot in Figure 5 is over the complex plane, and that squares (= "black vertices") represent points $x$ where $f(x) = 0$, while circles (= "white vertices") represent points $x$ where $f(x) = 1$. But how do you get Maple to produce this plot?

Answer 1

I was informed offline that the correct incantation is:

> plots[rootlocus](-1/f(x), x, 0 .. 1);