Operators $\square$, $\lozenge$ and $\rightarrow$ are defined by: $a \: \square \: b = \dfrac{a-b}{a+b}$; $a \: \lozenge \: b = \dfrac{a+b}{a-b}$; $a \rightarrow b = ab$. Find the value of $(66 \: \square \: 6) \rightarrow (66 \: \lozenge \: 6)$.

- $-2$
- $-1$
- $1$
- $2$