The three letter substitution rule whose scaling is the smallest PV number, the Plastic Number which is a root of the polynomial $x^3 - x - 1 = 0$
.
Though it might not look it at first glance, the Rauzy fractal is connected.
This can be shown using the method of A. Siegel described in [Sie04].
The Rauzy fractal:
[Sie04]
Siegel, Anne
Pure discrete spectrum dynamical system and periodic tiling associated with a substitution
Ann. Inst. Fourier (Grenoble)
2004,
54, 2,
pp. 341--381,