Weird, looks the same as all the others who do it. Obama and his wife, other politicians. What do you think about the triangle Trump makes with his hands? He has done it numerous times.
I don't know what to make of the triangles. Maybe they just mean I [heart] you. (just kidding.)
On an even less serious note, maybe GWB, being a baseball guy, was optimistically signaling "It's two outs for the other team, only one more to go."
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On a slightly more serious note, maybe it's just a gesture rubbing off on everyone, including politicos, from the gangstas and rappers. (Actually, I'm not kidding about that.)
Continuing in a serious vein, I would point out that in parts of Mexico, making what I would call the "Hook 'Em Horns" sign or the "Two Outs" sign and pointing the upright fingers into the face of an adversary is said to be a "Witches' Hex." (Again, no kidding.) But that doesn't equate it with the Illuminati as far as I'm concerned. It's not flagrant Satanism so much as it is a dopey superstition.
(Oh, I know that there are ancient historical connections of the two-finger sign with the occult, like the Babylonian stuff. Still, it means nothing if a person does it as a completely innocent wave of sorts. OTOH, when Gangsta Obama does something, it's likely not innocent--again, as far as I'm concerned. At the very least, I believe it's probably an evil reflex. [Well, I am halfway serious about that--and halfway not serious.])
Does this post cover the waterfront of possibilities to your satisfaction?