:(1:2) a

0 = {a = (5:2)}

0 = {a = (1:3)}

1 = {a = (1:2)}

:[1,2,3] b

0 = {b = a}

0 = {b = []}

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

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

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