Inequality

(x != x != x) evaluates to true when x is true.


Assuming x = true, (x != x != x) <=>
    ((x != x) != x) <=>
    ((true != true) != true) <=>
    (false != true) <=> true.
Assuming x = false, (x != x != x) <=>
    ((false != false) != false) <=>
    (false != false) <=> false.