\[\frac{1}{4}a^{4} + {2a}^{2}b^{2} + 4b^{4} =\]
\[= \left( \frac{1}{2}a^{2} + {2b}^{2} \right)^{2} =\]
\[= \left( \frac{1}{2}a^{2} + {2b}^{2} \right)\left( \frac{1}{2}a^{2} + {2b}^{2} \right)\]