Operators $\square$ , $\lozenge$ and ${\rightarrow}$ are defined by: $a\:\square \:b=\frac{a-b}{a+b}; \:a\:\lozenge \:b=\frac{a+b}{a-b};\:a\rightarrow b=ab.$

Find the value of $\left ( 66\:\square \:6 \right )\rightarrow \left ( 66\:\lozenge \:6\right ).$

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