::a = [1=2]

0 = {a == [5=2]!constant}

0 = {a == [1=3]!constant}

1 = {a == [1=2]!constant}

::b = [1,2,3]

0 = {b == a}

0 = {b == []!constant}

0 = {b == [3,1,2]!constant}

0 = {b == [1,2,3,4]!constant}

1 = {b == [1,2,3]!constant}

:c = [1,2,3]

0 = {c == b}

1 = {c!constant == b}

::d = [1,2,3]

1 = {d == b}