Think of how people point fingers at each other when they argue.
Version 1: The fingers go up and down together:
Version 2: The fingers uses an alternating movement.
Interesting -- I found that when I signed version 2 to myself
"off camera" I tended to open my mouth (a bit) and cover my bottom
teeth with my tongue. (Which is to say, my tongue was touching the
back/inner part of my lower lip but not protruding out of my mouth. But
I didn't use the tongue in the first version. I'll have to video other
people signing these two versions and see if anyone else does that.