Found that third method, the double rotational transposition for K3.

Double Rotation Transposition

It works.

Works great actually.

I’d like to say I prefer one method over another but they all have their charm.

I’d be curious to see if anyone’s found other methods.

I’d also be curious to somehow visualize how all of the methods are related.

For what it’s worth, the “Q” at the end of K3 seems legitimate.  The “?” is guaranteed by the #1 solution but left out of the gridding process in the #2 and #3 solutions I have posted.  Is this conclusive evidence one way or the other?  No.

It’d be nice to find some way to confirm the fact that it is 100% attached to K3, no doubts/no questions.

But is that really possible?