“A tautology is a tautology”...is a tautology. :)
4 = 4 is a tautology and so is 2 + 2 = 4.
Sometimes they are trivial and sometimes it takes a little work to realize that the 2 expressions are indeed the same, the definition of a tautology.
I know this is on a tangent but I've always like the simple fact that just because B followed A does not necessarily mean that A caused B. In modern liberal politics it is an oft used, convenient assumption/claim that proves false when examined in detail.
All we have to do now is to get the 4 expressions to agree with the 2.