Discussion on: The easiest problem you cannot solve.

[Tiago Romero Garcia]

These are less clever yet might be valid solutions:

K('')(cat)+K(dog)()
K()(cat);K(dog)()

[JavaScript Joel]

lol. Clearly I have to get better at writing rules! Technically these qualify!

[Tiago Romero Garcia]

One more:

K([cat,dog])()[1];