On a BBP-type formula for ${\pi }^2$ in the golden ratio base

This paper presents a detailed, self-contained proof of a BBP-type formula for ${\pi }^2$ expressed in the golden ratio base, $\phi$. The formula was discovered empirically by the author in 2004. The proof presented herein is built upon a fundamental geometric identity connecting $\phi$ to the fifth roots of unity, offering an intuitive and direct path to the result. The power of the underlying methodology is then demonstrated by extending it to establish a new, computationally efficient Machin-like formula for $\zeta (3)$, expressed through rapidly converging, hierarchical series involving the golden ratio.