$$(x+xy+ { y }^{ 2 } ) \times ( { x }^{ 2 } -xy+ { y }^{ 2 } )$$
$\left(x^{2}-xy+y^{2}\right)\left(xy+x+y^{2}\right)$
$x^{3}+xy^{2}+y^{4}+yx^{3}-yx^{2}$
