It is known that substitution system
$$ A \to ABA, B \to BBB $$
produces approximations to Cantor set: $$ A, ABA, ABABBBABA, ABABBBABABBBBBBBBBABABBBABA, \ ABABBBABABBBBBBBBBABABBBABABBBBBBBBBBBBBBBBBBBBBBBBBBBABABBBABABBBBBB\ BBBABABBBABA $$
I numerically estimated its dimension using naive box-counting method and got the value $D=0.62\pm0.01$
There are many other sequences that have fractal properties:
Simple kneading sequence: $A \to AB, B \to AA$
I tried to estimate their dimensions by various suitable methods, but I always got about 1.
So first question is:
Is there an example of a substitution system leading to the appearance of a fractal different from Cantor set with a fractal dimension $0 < D < 1$ ?
Second question much more difficult:
Is there any example of a substitution system produces multifractal?