What would be a concise way to get all adjacency matrices of size $n$, e.g. for $n=2$, these $(2^2)^2$ matrices:
{{0,0},
{0,0}}
{{1,0},
{0,0}}
{{0,1},
{0,0}}
{{0,0},
{1,0}}
{{0,0},
{0,1}}
{{1,1},
{0,0}}
{{1,0},
{1,0}}
{{1,0},
{0,1}}
{{0,1},
{1,0}}
{{0,1},
{0,1}}
{{0,0},
{1,1}}
{{1,1},
{1,0}}
{{1,1},
{0,1}}
{{0,1},
{1,1}}
{{1,0},
{1,1}}
{{1,1},
{1,1}}