This is a seemingly 'impossible' problem, because variously your function, "impossibleFn", must return an output of either 1 or 2 or 3 for the same input (0, the number zero). Why is this described as "seemingly impossible"? Because it does not satisfy the mathematical definition of a function. Yet there is still at least one way to pass all the tests! (One simple code has been verified to work. However, all's fair in this problem, so try whichever hacks and workarounds are at your disposal.) UPDATE: Now more than three (unrelated) approaches have been verified to pass all the tests.