Let $R$ be the ring $\mathbb{C}[x] /\left(x^{2}\right)$ obtained as the quotient of the polynomial ring $\mathbb{C}[x]$ by its ideal generated by $x^{2}$. Let $R^{\times}$be the multiplicative group of units of this ring. Then there is an injective group homomorphism from $(\mathbb{Z} / 2 \mathbb{Z}) \times(\mathbb{Z} / 2 \mathbb{Z})$ into $R^{\times}$.
